LECTURE N 2. - Meteorological Quantities and Climate Parameters - IDES-EDU

Size: px
Start display at page:

Download "LECTURE N 2. - Meteorological Quantities and Climate Parameters - IDES-EDU"

Transcription

1 Lecture contributions Coordinator of the lecture: Contributor : LECTURE N 2 - Meteorological Quantities and Climate Parameters - Prof. Marco Perino, DENERG Politecnico di Torino, C.so Duca degli Abruzzi 24, Torino, Dr. Valerio LoVerso Politecnico di Torino, C.so Duca degli Abruzzi 24, Torino, Prof. Marco Perino, DENERG Politecnico di Torino, C.so Duca degli Abruzzi 24, Torino,

2 INTRODUCTION Meteorological measurements for weather forecasting and climatology have been carried out on a regular basis for centuries. However, the data acquired can only be evaluated and interpreted after having statistically recorded medium-term and longterm atmospheric conditions. ES -E D All meteorological parameters are influenced by solar radiation, directly or indirectly, and this results in typical daily or yearly trends. All meteorological parameters are also subject to short-term variations, normally caused by turbulences within the atmosphere. U The main meteorological parameters significant for energy demand in buildings and for renewable energy industry are: Wind speed and direction Air temperature Air pressure Air humidity Solar and terrestrial radiation Precipitation THE AIR TEMPERATURE - 1 Air is heated by the sun indirectly: through a high wavelength radiation exchange with the ground (albedo) ID through a convection exchange with the ground through water vapor condensation and subsequent freezing processes, yielding evaporation and fusion heat being exchanged with air As a result: the air temperature shows a fluctuating trend with a double period: daily and Temperatur a dell aria yearly. 1 the daily maximum outdoor temperature, due to the atmospheric and solar energy Irraggiament o del Sole exchanges, typically occurs 2 3 hours 0 0 Irraggiament after the solar radiation reaches its o del suolo maximum value the minimum daily temperature value 0 6 happens at sun rise Typical daily variation of air temperature, in normal conditions, the air temperature decreases with the height from the sea Sun radiation, ground radiation level (around 0.65 C every 100 m) Radiation W/m2 Temperature C 2 0 2

3 THE AIR TEMPERATURE - 2 The connection between solar radiation throughout the year: and air temperature can be observed the lowest temperature values are recorded about one month after the winter solstice (i.e. lowest solar radiation), while the highest temperature values about one month after the summer solstice (i.e. highest solar radiation). THE AIR TEMPERATURE - 3 C Temperatura giornaliera [ C] (2) (1) Qualitative seasonal variation of air temperature (1) and solar radiation (2) DAILY VARIATION OF AIR TEMPERATURE AT DIFFERENT LATITUDES MARCH DECEMBER C ORA Irraggiamento [kwh/(m 2 giorno)] JUNE C 13 8 TEMPERATURA Turin TORINO TEMPERATURA Messina MESSINA TEMPERATURA Rome ROMA ORA 3

4 THE AIR TEMPERATURE - 4 Besides the daily cyclic variation, the air temperature shows stochastic components due to weather phenomena. These effects may be so high to completely change the predictable behavior due to the solar and atmospheric exchanges (so that a day may be characterized by air temperature values far different from those typical of the season). Nevertheless, if the homologous values (corresponding to the same hour of the same days for different years) are averaged over many years, the resulting daily temperature profiles show a recognizable, typical, periodic trend (stochastic influences are phased-out). Rarely the month average air temperatures differ from one year to other more than 2-3 C. -E D U Air temperature is also influenced by local features and phenomena (effect at meso and micro scale) and varies with the height from the ground. ES THE AIR TEMPERATURE - 5 Influencing factors at a meso-climatic and micro-climatic scale: TOPOGRAPHY ID water reservoirs depressions and bottomlands valleys TERRAIN SURFACE thermal inertia type of coverage and color LOCALITATION rural or urban area 4

5 THE AIR TEMPERATURE - 6 To characterize the air temperature of a location, the following values are usually adopted: average daily temperature (daily mean), average monthly temperature (monthly mean), average yearly temperature (annual mean), thermal excursion (the difference between the minimum and the maximum value of the daily outdoor air temperature) extreme (summer/winter) temperatures and time at which these peak values occur THE AIR TEMPERATURE - 7 Calculation of the average values: Daily mean If all the values at each hour of the day are known (measured), the daily mean can be assessed as the usual arithmetic average of all the values, lf the only available values are the daily maximum and minimum for each day of the month, the daily mean, θ dm, can be calculated as: θ dm θ = dmax + θ 2 dmin lf the only available values are those at certain times (usually: 07:30, 14:30 and 21:30), the daily mean, θ dm, can be calculated as: θ = + θ 3 + θ d7:30 d14:30 d21: 30 θdm 5

6 THE AIR TEMPERATURE - 8 Monthly mean If all the values at each hour of the month are known (measured), the monthly mean can be assessed as the usual arithmetic average of all the values, lf the only available values are the daily mean temperatures, θ dm, then θ mm can be calculated as: n θ mm = d= 1 Estimating the daily temperature profile (hourly) for the COOLING DESIGN DAY The daily air temperature profile can be approximated through the following function: Where: θ(τ) = θ θ n dm f( τ) dmax θ d,max θ dmax = maximum daily temperature, θ Max = maximum daily thermal excursion, f = reduction factor (given in the following table) THE AIR TEMPERATURE - 9 Estimating the daily temperature profile (hourly) for the COOLING DESIGN DAY The hourly reduction factor, f, is given hour by our for the design day: (From: Fracastoro, 1982) 6

7 THE AIR TEMPERATURE - 10 Estimating the daily temperature profile (hourly) for a GENERIC DAY The hourly profile of the air temperature during a generic day (24 hour) can be assessed through the following relation: Where: ( ) θ τ = θ + π sin 12 ( τ ϕ) π ( τ ϕ) + K K1 2 sin θ= daily mean temperature ϕ = phase angle = (τ Max -τ min )/2 K 1, K 2 = constants Constant K 1 and K 2 are obtained solving the following system: b θ ( ) K1 sin + K2 sin b = 2 2 b K1 cos + 2 K2 cos( b) = 0 2 Max Being: THE GROUND TEMPERATURE 6 b = π ϕ τ Max = time at which the maximum temperature occurs τ min = time at which the minimum temperature occurs The ground temperature is subject to the same periodic variations during the time as the air temperature, however its swing amplitude is far lower, thanks to the huge thermal mass of the soil. At few centimeters below the ground level the daily oscillation of the air temperature is practically undetectable. The ground temperature varies in time with a quite predictable law. This allows to obtain the time profile through a mathematical function, as proposed by Hadvig: Where: θ(h, τ) = θ y + A e π -h α Ys 2π cos Ys ( τ τ ) max - h θ(h,τ) = ground temperature at depth h and at time τ ( C) θ y = annual mean outdoor air temperature ( C) A = yearly thermal excursion ( C) Y s = year duration in seconds (that is: ) (s) τ max = instant of the year (in seconds) when the maximum outdoor air temperature is reached (s) α = thermal diffusivity of the soil (m 2 /s) π α Y s 7

8 THE RELATIVE HUMIDITY - 1 A small amount (grams per kilograms of dry air) of water vapor is present in the outdoor air. This water vapor derives from the evotraspiration phenomena (vegetation), evaporation from oceans, water reservoirs and the soil. Influencing factors at a meso-climatic and micro-climatic scale: TOPOGRAPHY VEGETATION evaporation process due to the presence of water masses evaporation-transpiration of tree leaves, which absorb most of the incident heat During winter time, since the outdoor air temperature is low, the specific humidity is very low (water vapor content per unit mass of dry air). Nevertheless, the RH is usually very high (75 % and above) for many hours of the season. In summer, instead, the water vapor content per unit mass of dry air may be 2 to 3 times higher than in winter, but RH is lower due to the high air temperature. THE RELATIVE HUMIDITY - 2 During the day the vapor pressure shows a rather constant trend with time (black curve in figure); as a result, relative humidity tends to increase when air temperature decreases and vice versa. DAILY VARIATION of RH 8

9 THE ATMOSPHERIC RADIATION - 1 The solar radiation, once has crossed the atmosphere, reaches the ground and is partly absorbed and partly reflected back towards the space. The absorbed quota heats up the soil causing a re-emission of radiation (in the range of IR between about µm, with a peak around 10 µm). This radiation is named terrestrial radiation. The terrestrial radiation is then mostly absorbed and reflected by the atmosphere, that, in turn, re-emits a radiative heat flux. The sum of the reflected terrestrial radiation and of the quota re-emitted by the atmosphere is named atmospheric radiation. The atmospheric radiation depends on: the quantity of water vapor in the atmosphere, the presence of clouds and the air temperature of the lower layers of the atmosphere. (From: Terry s Lab Website) THE ATMOSPHERIC RADIATION - 2 There are numerous relations to assess the atmospheric radiation. A simplified formula to evaluate the atmospheric radiation on an horizontal surface, G a [W/m 2 ], is the one proposed by Cole: G a = θ a + 65 c θ a c Where: θ a = air temperature [ C] c = cloud cover factor (fraction of the sky covered by clouds) [-] 2 [ W/m ] For inclined surface, G a can be corrected by means of the following relation: G a 2 ( Σ) = G K + b K σ θ [ W/m ] a Where: Σ = is the tilt angle with respect to the horizontal 1 2 a 9

10 THE ATMOSPHERIC RADIATION - 3 Coefficients K 1 and k 2 are given in the following table: (From: Fracastoro, 1982) b can be assessed through the following relation: b = c θ SOLAR RADIATION AND WIND Due to the ample extent of information needed in relation to solar radiation and wind, for designing buildings and energy systems based on RES, these quantities will be thoroughly dealt with in the following lectures. In particular : Lectures 3 will treat the topics: SOLAR ENERGY AND SOLAR RADIATION, Lectures 4 will treat the topic: AVAILABLE SOLAR RADIATION, Lectures 6 will treat the topics: WIND AND WIND ENERGY. a c 10

11 CLIMATE PARAMETERS THE SOL-AIR TEMPERATURE - 1 Sol-air temperature, θ sol-air, is the fictitious outdoor air temperature that, in the absence of all radiation exchanges on the outer surface of the building envelope, gives rise to the same heat flux through the surface as would the combination of incident solar radiation, radiant energy exchange with the sky and other outdoor surroundings and convective heat exchange with outdoor air. G T θ equivalent θ sol-air 11

12 THE SOL-AIR TEMPERATURE - 2 Sol-air temperature, θ sol-air, can be assessed through the following relation: θ α G = θ + ε R T sol air (1) h o ho α = absorptance of surface for solar radiation [-] G T = total solar radiation incident on the surface [W/(m 2 )] h o = surface heat transfer coefficient by long-wave radiation and convection at outer surface [W/(m 2 K)] θ = outdoor air temperature, [ C] ε = hemispherical emittance of surface [-] R = difference between long-wave radiation incident on surface from sky and surroundings and radiation emitted by blackbody at outdoor air emperature [W/m 2 ] For many practical cases θ sol-air can be assessed, with a sufficient approximation, with a simplified relation obtained assuming R = 0. DESIGN CONDITIONS - 1 Outdoor design conditions must represent the worst, most severe, scenarios that the building and the HVAC system are asked to cope with. It has to be underlined that these conditions are not the worst-of-all weather conditions experienced over the years in a location, but they must represent the statistically relevant worst conditions (those which typically occur from time to time). ASHARE suggests to adopt the following criteria to select the design conditions: Design conditions for warm-season: outdoor air temperature and humidity are based on annual percentiles of 0.4 %, 1.0 %, and 2.0 %. Design conditions for cold-season: are based on annual percentiles of 99.6 % and 99.0 % of the outdoor air temperature. The use of annual percentiles to define design conditions ensures that they represent the same probability of occurrence in any climate, regardless of the seasonal distribution of extreme temperature and humidity. In many countries outdoor design conditions are defined in technical standards and fixed by law. 12

13 DESIGN CONDITIONS - 2 Design data based on dry-bulb temperature represent peak occurrences of the sensible component of ambient outdoor conditions. Design values based on wet-bulb temperature are related to the enthalpy of the outdoor air. Conditions based on dew point relate to the peaks of the humidity ratio. The designer, engineer, or other user must decide which set(s) of conditions and probability of occurrence apply to the design situation under consideration; as a general rule: The 99.6 and 99.0% design conditions are often used in sizing heating equipment. The 0.4, 1.0, and 2.0% dry-bulb temperatures and mean coincident wet-bulb temperatures often represent conditions on hot, mostly sunny days. These are often used in sizing cooling equipment such as chillers or air-conditioning units. Design conditions based on wet-bulb temperature represent extremes of the total sensible plus latent heat of outdoor air. This information is useful for cooling towers, evaporative coolers, and fresh air ventilation system design. DESIGN CONDITIONS DIFFERENT APPROACH BETWEEN HEATING AND COOLING SYSTEMS Design conditions for heating systems 10 usually refer to a fixed condition, 8 corresponding to the statistically worst 6 Heating 4 hour of the year as far as heating demand 2 0 is concerned. This is due to the fact that design procedures for heating system -6 (specially in case of simpler systems) is based on a steady-state calculation -12 Days (therefore a single point condition is sufficient). In case of cooling systems design, it is necessary to rely on calculation methods based on non steady-state regime, able to quantify the energy storage/release of the building structures and furniture's (thermal mass) and the thermal dynamics. This implies that a time profile of the design Cooling conditions is required. Typically a design day (e.g. an infinite sequence of 24 hourly values) has to be defined. Outdoor air Temp. [ C] 13

14 ANNUAL HEATING AND HUMIDIFICATION DESIGN CONDITIONS ASHRAE suggests to adopt the following meteorological parameters to establish the heating design conditions: Choose the coldest month (i.e., month with lowest average dry-bulb temperature); Assess the dry-bulb temperature corresponding to 99.6 and 99.0% annual cumulative frequency of occurrence (statistically relevant coldest conditions); Assess the dew-point temperature corresponding to 99.6 and 99.0% annual cumulative frequency of occurrence and the corresponding specific humidity, calculated at standard atmospheric pressure at elevation of station (grams of moisture per kg of dry air) and mean coincident dry-bulb temperature; Assess the wind speed corresponding to 0.4 and 1.0% cumulative frequency of occurrence for coldest month; Assess the mean wind speed coincident with 99.6% dry-bulb temperature and the corresponding most frequent wind direction. ANNUAL COOLING AND DEHUMIDIFICATION DESIGN CONDITIONS - 1 ASHRAE suggests to adopt the following meteorological parameters to establish the cooling design conditions: Choose the hottest month (i.e., month with highest average dry-bulb temperature); Assess the daily temperature range for hottest month (defined as the mean of the difference between daily maximum and daily minimum dry-bulb temperatures for hottest month); Assess the dry-bulb temperature corresponding to 0.4, 1.0, and 2.0% annual cumulative frequency of occurrence (statistically relevant warmest conditions), Assess the wet-bulb temperature corresponding to 0.4, 1.0, and 2.0% annual cumulative frequency of occurrence and the mean coincident dry-bulb temperature and the corresponding mean coincident dry-bulb temperature; Assess the mean wind speed coincident with 0.4% dry-bulb temperature and the corresponding most frequent wind direction (degrees from north); Cont d 14

15 ANNUAL COOLING AND DEHUMIDIFICATION DESIGN CONDITIONS - 2 Summer design day U Assess the dew-point temperature corresponding to 0.4, 1.0, and 2.0% annual cumulative frequency of occurrence and the corresponding humidity ratio, calculated at the standard atmospheric pressure at elevation of station (g of moisture per kg of dry air) and mean coincident dry-bulb temperature; Assess the enthalpy corresponding to 0.4, 1.0, and 2.0% annual cumulative frequency of occurrence and the mean coincident dry-bulb temperature. Day from any calendar month with a specified return period for extreme values of the significant meteorological parameters (usually dry bulb temperature). ES -E D It is a series of 24 hourly values of: temperature, temperature swing, dew point (or RH), solar irradiation and wind speed EXTREME DESIGN CONDITIONS In case of critical applications design, where even an occasional short-duration capacity shortfall is not acceptable, ASHRAE suggests to adopt the following extreme annual design conditions: ID Wind speed corresponding to 1.0, 2.5, and 5.0% annual cumulative frequency of occurrence, m/s. Extreme maximum wet-bulb temperature, C , 10-, 20-, and 50-year return period values for maximum and minimum extreme dry-bulb temperature, C. 15

16 THE DEGREE DAY CONCEPT - 1 The degree days refer to the concept of accumulated temperature differences. Degree days are a relatively simple form of climatic data, useful as an index of climate severity. Energy consumption for space heating and cooling is a function of the degree days. Calculation or estimation of degree days needs to introduce the concept of a base temperature, θ b. In theory, the base temperature should reflect the point at which buildings begin to need heating or cooling to maintain the required internal temperatures. However, the base temperatures are freqeuntly established and fixed conventionally, at national level, through technical standards and/or decree and laws. A degree day is computed as the integral of a function of time that generally varies with temperature. The function is truncated to upper and lower limits that vary by organism, or to limits that are appropriate for climate control. The assessment of the degree days is different between heating period (HDD = Heating Degree Days) and the cooling period (CDD = Cooling Degree Days) THE DEGREE DAY CONCEPT - 2 The degree day is, therefore, a measure of heating or cooling requirements. Degree days may be used for the following purposes: a) monitoring the amount of energy used by heating/cooling plant, and thus its efficiency (the energy management use); b) providing an index of climatic severity as it affects energy use for space heating and cooling (the comparison use); c) comparing the actual energy consumption for heating/cooling in a specific period with the consumption in a standardized period, in order to determine the operational rating (the energy modeling use); d) predicting, on a preliminary level, the economic consequences of different interventions for energy efficiency (e.g. thermal insulation) (the energy policy use). 16

17 THE DEGREE DAY CONCEPT - 3 Energy management (purpose a) requires the assessment of new degree days data at regular intervals. These degree days are calculated from actual meteorological quantities measured at weather stations. They reflect the real weather conditions, vary year by year and are calculated, on the basis of standard base temperatures. They are, usually, published for each month of the heating/cooling season, as soon as these can be computed from verified meteorological observations. Comparison, energy modeling and energy policy purposes (b, c and d), require degree days representative of the typical climate of a region (and not of actual weather data related to a certain month or season). For this reason they must be assessed on the basis of data collected over many years (possibly giving extremes as well as mean values), to typify the severity of the climate of a locality, area or region. THE HEATING DEGREE DAY (HDD) - 1 Heating degree day (HDD) provides a simple metric for quantifying the amount of heating that buildings in a particular location need over a certain period (e.g. a particular month or year). Heating degree days are a measure of the severity and duration of cold weather. The colder the weather in a given month, the larger the degree-day value for that month. The heating requirements for a given building at a specific location can be roughly considered to be directly proportional to the number of HDD at that location (In conjunction with the average U- value for a building and the average ventilation loss coefficient they, they provide a means of roughly estimating the amount of energy required to heat the building over that period). 17

18 THE HEATING DEGREE DAY (HDD) - 2 One HDD means that the temperature conditions outside the building were equivalent to being below a defined threshold comfort temperature inside the building by one degree for one day. Thus heat has to be provided inside the building to maintain thermal comfort. HDD can be added over periods of time. Heating degree days are defined relative to a base temperature, θ b, and a threshold temperature, θ th. The most appropriate base temperature for any particular building depends on indoor building conditions. The threshold temperature is the outside temperature above which a building needs no heating. Therefore, θ th, for any particular building depends on indoor building conditions (set point temperature) and the nature of the building (including the heatgenerating occupants and equipment within it). For calculations relating to any particular building, HDD should be selected with the most appropriate base and threshold temperatures for that building. However, for practical reasons HDD are often made available with conventional base temperatures and heating periods. THE HEATING DEGREE DAY (HDD) - 3 HDD are usually calculated using simple approximation methods that adopt daily temperature readings instead of more detailed temperature records, such as hourly readings. One popular approximation method is to take the average temperature on any given day, and subtract it from the base temperature. If the value is less than or equal to zero, that day has zero HDD. If the value is positive, that number represents the number of HDD on that day: Where: HDD = τ τ N 0 + ( θ θ ) dτ = ( θ θ ) b dm N d= 1 θ b = base temperature, θ dm = daily mean temperature, τ = time N = number of days in the heating (cooling) season b + dm d [ C day] Superscript + means that only positive differences have to be considered 18

19 THE HEATING DEGREE DAY (HDD) - 4 In theory the value of N is determined choosing the threshold outdoor air temperature, θ th (daily mean). This is the outside daily mean temperature above which a building needs no heating (typically 12 C, but its value can vary according to the building type, location and internal conditions). Nevertheless, N is frequently fixed at national level, by means of technical standard and/or laws, decrees. θ θ b θ th θ dm τ 0 N HDD THE COOLING DEGREE DAY (CDD) - 1 τ N Day cooling degree day (CDD) provides a simple metric for quantifying the amount of cooling that buildings in a particular location need over a certain period (e.g. a particular month or year). While method to assess the HDD is well established, the method for calculating the cooling degree days is not unique. According to the most often adopted definition, cooling degree-days (CDD) are calculated as: τn N + + CDD = ( θdm θb ) dτ = ( θdm θb ) [ C day] d τ d= 1 Where: 0 θ b = base temperature, θ dm = daily mean temperature, τ = time N = number of days in the heating (cooling) season The plus sign (+) of the equation indicates that only positive values are to be counted, meaning that if θ dm < θ b then CDD = 0. 19

20 THE COOLING DEGREE DAY (CDD) - 2 Daily values of CDD are summed to calculate the total number of cooling degreedays over a period in question. Other methods for assessing CDD can be found in the literature. Calculation of CDD can be achieved by using monthly-average daily temperatures as well as monthly-average solar radiation and ambient temperature data in combination (sol-air temperature degree days). DEGREE DAYS AND BUILDINGS DYNAMIC ENERGY SIMULATION Degree days are suited to roughly assess the energy performance of relatively small buildings with simple heating systems and controls, using quasi steady-state thermal analysis. A more reliable calculation of the energy performance of a building, or the modeling of the performance of larger and more complex buildings, cannot be done with the degree days concept. In such cases more extensive climatological data sets are needed, such as full or short reference weather year. Software are available to simulate the annual energy performance of buildings requiring a 1-year data set (8760 records, one for each hour of the year) of weather conditions (that is a reference weather year ). 20

21 BUILDINGS DYNAMIC ENERGY SIMULATION AND METEO DATA - 1 A reference weather year (variously known as Test Reference Year - TRY, Typical Meteorological Year - TMY, International Weather Years for Energy Calculations IWECs, ) is a single year of hourly data (8760 hours), selected to represent the range of weather patterns that would typically be found in a multi-year dataset. Therefore, it is a sort of average year or typical year for a given location and time frame. It is intended to allow more economical simulation than multi-year datasets, and to form an equitable basis for comparing the predicted typical energy consumptions of different building designs and, in some cases, the typical performance of solar collectors. ES -E D U Definition of a Reference Year depends on satisfying a set of statistical tests relating it to the multi-year parent dataset, from which it is drawn. Some sources have preferred to identify a continuous, 12-month period, as typical; whereas others have applied the criteria to individual months, subsequently assembled into a composite 12-month year. BUILDINGS DYNAMIC ENERGY SIMULATION AND METEO DATA - 2 ID Many data sets in different record formats have been developed to meet these requirements. The reference weather data, typically and traditionally used in building and solar energy simulations, are: International Weather for Energy Calculations (IWYEC) and Typical Meteorological Year (TMY, Type 2 and 3) in the United States and Canada, the Test Reference Year (TRY) in Europe. These data represent a typical year with respect to weather-induced energy loads on a building. The main difference between the various type of reference weather years (TRY, TMY, IWEC) lies in the way data are collected, analyzed and assembled. LIMITATIONS: because reference weather years represent typical and average (over long periods) rather than extreme conditions: they do not meet the worst-case conditions occurring at a location, therefore they are NOT SUITED FOR DESIGNING SYSTEMS. no indication of the full range of possible conditions is given, therefore there are several issues when considering, peak heating loads, human comfort or overheating levels. 21

22 TYPICAL METEOROLOGICAL YEAR - TMY A typical meteorological year (TMY) is a data set of hourly values of solar radiation and meteorological quantities for a 1-year periods, for a specific location, generated from a data set much longer than a year in duration. The data set is created through selecting, by statistical methods, one Typical Meteorological Month (TMM) for each of the 12 calendar months from a period of years (preferably 30) of data and concatenating the 12 months to form a TMY. The final TMY file consists of hourly data for an annual period, but each month is from a different year. There exist different formats for TMY (TMY2, TMY3). U TMY represents the range of weather phenomena for the location in question, while still giving annual averages that are consistent with the long-term averages for the location. ES -E D Their intended use is for computer simulations of solar energy conversion systems and building systems to facilitate performance comparisons of different system types, configurations, and locations. For example, EnergyPlus, TRNSYS and PVSOL support simulations using TMY. TEST REFERNCE YEAR - TRY ID A test Reference Year (TRY) is a data set with a structure similar to that of the TMY. It is a 1-year sequences of 8760 hourly values of: dry bulb temperature, vapor pressure (or other humidity parameter), global solar radiation or both direct and diffuse radiation on a horizontal surface and wind speed at a height of 10 meters, together with the date and time stamps. The details (location and altitude) of the station, the period of the original data set and the years from which the individual months were taken shall be reported. The main difference between the TMY and the TRY is the procedure and the statistical methods used to assemble the data from databases constituted by 10, 20 or 30 years of measured data. Care has to be taken since different assembling methods are used in different countries to create TRY. One great limitation involved in the creation of a TRY weather file is that, frequently, it does not contain any measured solar radiation values. Reported radiation data are often estimated and obtained through calculation of solar radiation based on the cloud cover factors and cloud type. 22

23 INTERNATIONAL WEATHER FOR ENERGY CALCULATIONS (IWEC WEATHER FILES) - 1 The selection criteria for the ASHRAE International Weather Years for Energy Calculations (IWECs) files is similar to the TMY selection process, but instead uses nine weighted weather parameters. IWECs data sets contain "typical" weather data in ASCII format (a header and 8760 hourly records). ES -E D U The International Weather for Energy Calculation (IWEC) files are derived from up to 18 years of hourly weather data. The weather data is supplemented by solar radiations estimated on an hourly basis from earth-sun geometry and hourly weather elements (cloud cover, atmospheric features). INTERNATIONAL WEATHER FOR ENERGY CALCULATIONS (IWEC WEATHER FILES) - 2 The IWEC files are well suited to the following uses: ID Input to building energy hourly simulation software (such as DOE-2, BLAST or EnergyPlus) to estimate the typical annual energy consumption of buildings. The IWEC files are not suited to the following uses: simulation of wind energy and/or solar energy systems (the weights used for the selection of typical months are heavily biased toward dry bulb temperature and solar radiation is estimated). Sizing of systems. The IWEC files are 'typical years' that normally stay away from extreme conditions. 23

24 ARTIFICAILLY GENERATED TMY Weather data are not available for any site worldwide. Moreover, for many sites the data are available in an aggregated form (e.g. daily or monthly average values). Furthermore, measured data when existing are typically referred to a weather station that can be further apart from the building location. In these cases, software are needed to calculate hourly values from the monthly values using stochastic models and to interpolated between weather stations. Generally, a statistical approach should be considered as a last resort. Weather files generated from statistics will not exactly match the normal hour-to-hour and day-today variability seen in measured data. ES -E D U An example of software suited for these purposes is Meteonorm (meteonorm.com). The program's calculation algorithms provide the basis for generating hourly values for global radiation, temperature and other meteorological parameters. The resulting time series correspond to "typical years". A sophisticated interpolation models allows a calculation of at any site in the world. CARE IN USING METEOROLOGICAL QUANTITIES AND CLIMATE PARAMETERS ID Most of the observed data for which design/typical conditions were assessed are collected from airport observing sites, the majority of which are flat, grassy, open areas, away from buildings and trees or other local influences. Temperatures recorded in these areas may be significantly different (3 to 5 C lower) compared to areas where the design conditions are being applied. Significant variations can also occur with changes in local elevation, across large metropolitan areas, or in the vicinity of large bodies of water. Judgment must always be exercised in assessing the representativeness of the design conditions. Wind speed and direction are very sensitive to local exposure features, such as terrain and surface cover. The original wind data used to calculate the wind speed and direction design conditions are often representative of a flat, open exposure, such as at airports. Wind engineering methods can be used to account for exposure differences between airport and building sites. These topics will be dealt with in lectures 7 and 8. 24

25 References and relevant bibliography 2005 ASHRAE Handbook of Fundamentals - Chapter 28 Climatic Design Information, ASHRAE, Atlanta, USA, Elementi di Climatologia Edilizia, G. Fracastoro, Ed. Celid ISBN , Torino, Italy, 1982 Standard EN-ISO parts 1, 2, 4 and

ASHRAE Climatic Data Activities. Dru Crawley Didier Thevenard

ASHRAE Climatic Data Activities. Dru Crawley Didier Thevenard ASHRAE Climatic Data Activities Dru Crawley Didier Thevenard ASHRAE American Society of Heating Refrigerating and Air- Conditioning Engineers >50,000 members Major products: Handbooks (Fundamentals, Systems

More information

Optimum Solar Orientation: Miami, Florida

Optimum Solar Orientation: Miami, Florida Optimum Solar Orientation: Miami, Florida The orientation of architecture in relation to the sun is likely the most significant connection that we can make to place in regards to energy efficiency. In

More information

Low temperature solar assisted (heating) system based on slurry PCM

Low temperature solar assisted (heating) system based on slurry PCM ANNEX 59 - High emperature Cooling & Low emperature Heating in Buildings Riqualificazione di edifici esistenti con elevati standard energetici: metodi e tecnologie ENEA - Via G. Romano 41, 00196 Roma -

More information

Climate and Weather. This document explains where we obtain weather and climate data and how we incorporate it into metrics:

Climate and Weather. This document explains where we obtain weather and climate data and how we incorporate it into metrics: OVERVIEW Climate and Weather The climate of the area where your property is located and the annual fluctuations you experience in weather conditions can affect how much energy you need to operate your

More information

Seasonal & Daily Temperatures. Seasons & Sun's Distance. Solstice & Equinox. Seasons & Solar Intensity

Seasonal & Daily Temperatures. Seasons & Sun's Distance. Solstice & Equinox. Seasons & Solar Intensity Seasonal & Daily Temperatures Seasons & Sun's Distance The role of Earth's tilt, revolution, & rotation in causing spatial, seasonal, & daily temperature variations Please read Chapter 3 in Ahrens Figure

More information

Green Building Handbook for South Africa Chapter: Heating, Ventilation and Cooling Luke Osburn CSIR Built Environment

Green Building Handbook for South Africa Chapter: Heating, Ventilation and Cooling Luke Osburn CSIR Built Environment Green Building Handbook for South Africa Chapter: Heating, Ventilation and Cooling Luke Osburn CSIR Built Environment The heating, ventilation and cooling loads of typical commercial office space can range

More information

Seasonal Temperature Variations

Seasonal Temperature Variations Seasonal and Daily Temperatures Fig. 3-CO, p. 54 Seasonal Temperature Variations What causes the seasons What governs the seasons is the amount of solar radiation reaching the ground What two primary factors

More information

ESCI 107/109 The Atmosphere Lesson 2 Solar and Terrestrial Radiation

ESCI 107/109 The Atmosphere Lesson 2 Solar and Terrestrial Radiation ESCI 107/109 The Atmosphere Lesson 2 Solar and Terrestrial Radiation Reading: Meteorology Today, Chapters 2 and 3 EARTH-SUN GEOMETRY The Earth has an elliptical orbit around the sun The average Earth-Sun

More information

Fundamentals of Climate Change (PCC 587): Water Vapor

Fundamentals of Climate Change (PCC 587): Water Vapor Fundamentals of Climate Change (PCC 587): Water Vapor DARGAN M. W. FRIERSON UNIVERSITY OF WASHINGTON, DEPARTMENT OF ATMOSPHERIC SCIENCES DAY 2: 9/30/13 Water Water is a remarkable molecule Water vapor

More information

ES 106 Laboratory # 6 MOISTURE IN THE ATMOSPHERE

ES 106 Laboratory # 6 MOISTURE IN THE ATMOSPHERE ES 106 Laboratory # 6 MOISTURE IN THE ATMOSPHERE 6-1 Introduction By observing, recording, and analyzing weather conditions, meteorologists attempt to define the principles that control the complex interactions

More information

CHAPTER 3. BUILDING THERMAL LOAD ESTIMATION

CHAPTER 3. BUILDING THERMAL LOAD ESTIMATION CHAPTER 3. BUILDING THERMAL LOAD ESTIMATION 3.1 Purpose of Thermal Load Estimation 3.2 Heating Load versus Cooling Load 3.3 Critical Conditions for Design 3.4 Manual versus Computer Calculations 3.5 Heating

More information

Energy Pathways in Earth s Atmosphere

Energy Pathways in Earth s Atmosphere BRSP - 10 Page 1 Solar radiation reaching Earth s atmosphere includes a wide spectrum of wavelengths. In addition to visible light there is radiation of higher energy and shorter wavelength called ultraviolet

More information

Software Development for Cooling Load Estimation by CLTD Method

Software Development for Cooling Load Estimation by CLTD Method IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) ISSN: 2278-1684Volume 3, Issue 6 (Nov. - Dec. 2012), PP 01-06 Software Development for Cooling Load Estimation by CLTD Method Tousif Ahmed Department

More information

CHAPTER 3. The sun and the seasons. Locating the position of the sun

CHAPTER 3. The sun and the seasons. Locating the position of the sun zenith 90 summer solstice 75 equinox 52 winter solstice 29 altitude angles observer Figure 3.1: Solar noon altitude angles for Melbourne SOUTH winter midday shadow WEST summer midday shadow summer EAST

More information

Solar Flux and Flux Density. Lecture 3: Global Energy Cycle. Solar Energy Incident On the Earth. Solar Flux Density Reaching Earth

Solar Flux and Flux Density. Lecture 3: Global Energy Cycle. Solar Energy Incident On the Earth. Solar Flux Density Reaching Earth Lecture 3: Global Energy Cycle Solar Flux and Flux Density Planetary energy balance Greenhouse Effect Vertical energy balance Latitudinal energy balance Seasonal and diurnal cycles Solar Luminosity (L)

More information

1. Theoretical background

1. Theoretical background 1. Theoretical background We consider the energy budget at the soil surface (equation 1). Energy flux components absorbed or emitted by the soil surface are: net radiation, latent heat flux, sensible heat

More information

AIRCONDITIONING Cooling Loads Calculations

AIRCONDITIONING Cooling Loads Calculations Calculations -1- AIRCONDITIONING Cooling s Calculations Employer : 4M SA Project Location : ASHRAE Office Room : Example from ASHRAE 2013 Handbook - Fundamentals : Chapter 18, Single Room Example (p. 18.37)

More information

Application of Building Energy Simulation to Air-conditioning Design

Application of Building Energy Simulation to Air-conditioning Design Hui, S. C. M. and K. P. Cheung, 1998. Application of building energy simulation to air-conditioning design, In Proc. of the Mainland-Hong Kong HVAC Seminar '98, 23-25 March 1998, Beijing, pp. 12-20. (in

More information

Chapter 2: Solar Radiation and Seasons

Chapter 2: Solar Radiation and Seasons Chapter 2: Solar Radiation and Seasons Spectrum of Radiation Intensity and Peak Wavelength of Radiation Solar (shortwave) Radiation Terrestrial (longwave) Radiations How to Change Air Temperature? Add

More information

ATM S 111, Global Warming: Understanding the Forecast

ATM S 111, Global Warming: Understanding the Forecast ATM S 111, Global Warming: Understanding the Forecast DARGAN M. W. FRIERSON DEPARTMENT OF ATMOSPHERIC SCIENCES DAY 1: OCTOBER 1, 2015 Outline How exactly the Sun heats the Earth How strong? Important concept

More information

Eco Pelmet Modelling and Assessment. CFD Based Study. Report Number 610.14351-R1D1. 13 January 2015

Eco Pelmet Modelling and Assessment. CFD Based Study. Report Number 610.14351-R1D1. 13 January 2015 EcoPelmet Pty Ltd c/- Geoff Hesford Engineering 45 Market Street FREMANTLE WA 6160 Version: Page 2 PREPARED BY: ABN 29 001 584 612 2 Lincoln Street Lane Cove NSW 2066 Australia (PO Box 176 Lane Cove NSW

More information

Solar Heating Basics. 2007 Page 1. a lot on the shape, colour, and texture of the surrounding

Solar Heating Basics. 2007 Page 1. a lot on the shape, colour, and texture of the surrounding 2007 Page 1 Solar Heating Basics Reflected radiation is solar energy received by collectorsfrom adjacent surfaces of the building or ground. It depends a lot on the shape, colour, and texture of the surrounding

More information

Exploring the Building Energy Impacts of Green Roof Design Decisions - A Modeling Study of Buildings in 4 Distinct Climates

Exploring the Building Energy Impacts of Green Roof Design Decisions - A Modeling Study of Buildings in 4 Distinct Climates Final version for publication: Exploring the Building Energy Impacts of Green Roof Design Decisions - A Modeling Study of Buildings in 4 Distinct Climates David J. Sailor 1, Timothy B. Elley 2, and Max

More information

Diego Ibarra Christoph Reinhart Harvard Graduate School of Design

Diego Ibarra Christoph Reinhart Harvard Graduate School of Design Building Performance Simulation for Designers - Energy DesignBuilder // EnergyPlus Tutorial #2 Load Schedules GEOMETRY LOADS RESULTS Diego Ibarra Christoph Reinhart Harvard Graduate School of Design OVERVIEW

More information

Passive Solar Design and Concepts

Passive Solar Design and Concepts Passive Solar Design and Concepts Daylighting 1 Passive Solar Heating Good architecture? The judicious use of south glazing coupled with appropriate shading and thermal mass. Summer Winter Passive solar

More information

Climate and Energy Responsive Housing in Continental Climates. The Suitability of Passive Houses for Iran's Dry and Cold Climate. Farshad Nasrollahi

Climate and Energy Responsive Housing in Continental Climates. The Suitability of Passive Houses for Iran's Dry and Cold Climate. Farshad Nasrollahi Climate and Energy Responsive Housing in Continental Climates The Suitability of Passive Houses for Iran's Dry and Cold Climate Farshad Nasrollahi Table of Contents Abstract German Abstract Introduction

More information

CHAPTER 2 Energy and Earth

CHAPTER 2 Energy and Earth CHAPTER 2 Energy and Earth This chapter is concerned with the nature of energy and how it interacts with Earth. At this stage we are looking at energy in an abstract form though relate it to how it affect

More information

How do I measure the amount of water vapor in the air?

How do I measure the amount of water vapor in the air? How do I measure the amount of water vapor in the air? Materials 2 Centigrade Thermometers Gauze Fan Rubber Band Tape Overview Water vapor is a very important gas in the atmosphere and can influence many

More information

ES 106 Laboratory # 5 EARTH-SUN RELATIONS AND ATMOSPHERIC HEATING

ES 106 Laboratory # 5 EARTH-SUN RELATIONS AND ATMOSPHERIC HEATING ES 106 Laboratory # 5 EARTH-SUN RELATIONS AND ATMOSPHERIC HEATING 5-1 Introduction Weather is the state of the atmosphere at a particular place for a short period of time. The condition of the atmosphere

More information

User Perspectives on Project Feasibility Data

User Perspectives on Project Feasibility Data User Perspectives on Project Feasibility Data Marcel Šúri Tomáš Cebecauer GeoModel Solar s.r.o., Bratislava, Slovakia marcel.suri@geomodel.eu http://geomodelsolar.eu http://solargis.info Solar Resources

More information

Residential HVAC System Sizing

Residential HVAC System Sizing Residential HVAC System Sizing William P. Goss University of Massachusetts, Amherst, Massachusetts, USA Corresponding email: goss@acad.umass.edu SUMMARY Heating, ventilating and air-conditioning (HVAC)

More information

Solar Energy. Outline. Solar radiation. What is light?-- Electromagnetic Radiation. Light - Electromagnetic wave spectrum. Electromagnetic Radiation

Solar Energy. Outline. Solar radiation. What is light?-- Electromagnetic Radiation. Light - Electromagnetic wave spectrum. Electromagnetic Radiation Outline MAE 493R/593V- Renewable Energy Devices Solar Energy Electromagnetic wave Solar spectrum Solar global radiation Solar thermal energy Solar thermal collectors Solar thermal power plants Photovoltaics

More information

LECTURE N 3. - Solar Energy and Solar Radiation- IDES-EDU

LECTURE N 3. - Solar Energy and Solar Radiation- IDES-EDU LECTURE N 3 - Solar Energy and Solar Radiation- Lecture contributions Coordinator & contributor of the lecture: Prof. Marco Perino, DENERG Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino,

More information

Cooling Load Calculations and Principles

Cooling Load Calculations and Principles Cooling Load Calculations and Principles Course No: M06-004 Credit: 6 PDH A. Bhatia Continuing Education and Development, Inc. 9 Greyridge Farm Court Stony Point, NY 10980 P: (877) 322-5800 F: (877) 322-4774

More information

Absolute and relative humidity Precise and comfort air-conditioning

Absolute and relative humidity Precise and comfort air-conditioning Absolute and relative humidity Precise and comfort air-conditioning Trends and best practices in data centers Compiled by: CONTEG Date: 30. 3. 2010 Version: 1.11 EN 2013 CONTEG. All rights reserved. No

More information

FLORIDA SOLAR ENERGY CENTER

FLORIDA SOLAR ENERGY CENTER FLORIDA SOLAR ENERGY CENTER Creating Energy Independence Since 1975 Impact of Energy-Efficiency Parameters on Home Humidity Rob Vieira Florida Solar Energy Center A Research Institute of the University

More information

Opening the Bonnet. Prof Darren Woolf WYSINWYG 1

Opening the Bonnet. Prof Darren Woolf WYSINWYG 1 Opening the Bonnet Prof Darren Woolf WYSINWYG 1 WYSINWYG What You See Is NOT What You Get: Looking inside the Pandora s Box Prof Darren Woolf WYSINWYG 2 WYSIWYG implies a user interface that allows the

More information

Moisture Control. It s The Dew Point. Stupid! Its not the humidity.

Moisture Control. It s The Dew Point. Stupid! Its not the humidity. Moisture Control Its not the humidity. It s The Dew Point Stupid! Mike Schell EpiphanyTec Inc. Santa Barbara, CA mschell@epiphanytec.com 805 687-3175 Matching great technology to market need! Topics SHR

More information

ALONE. small scale solar cooling device Project No TREN FP7EN 218952. Project No TREN/FP7EN/218952 ALONE. small scale solar cooling device

ALONE. small scale solar cooling device Project No TREN FP7EN 218952. Project No TREN/FP7EN/218952 ALONE. small scale solar cooling device Project No TREN/FP7EN/218952 ALONE small scale solar cooling device Collaborative Project Small or Medium-scale Focused Research Project DELIVERABLE D5.2 Start date of the project: October 2008, Duration:

More information

EXPLANATION OF WEATHER ELEMENTS AND VARIABLES FOR THE DAVIS VANTAGE PRO 2 MIDSTREAM WEATHER STATION

EXPLANATION OF WEATHER ELEMENTS AND VARIABLES FOR THE DAVIS VANTAGE PRO 2 MIDSTREAM WEATHER STATION EXPLANATION OF WEATHER ELEMENTS AND VARIABLES FOR THE DAVIS VANTAGE PRO 2 MIDSTREAM WEATHER STATION The Weather Envoy consists of two parts: the Davis Vantage Pro 2 Integrated Sensor Suite (ISS) and the

More information

RADIATION IN THE TROPICAL ATMOSPHERE and the SAHEL SURFACE HEAT BALANCE. Peter J. Lamb. Cooperative Institute for Mesoscale Meteorological Studies

RADIATION IN THE TROPICAL ATMOSPHERE and the SAHEL SURFACE HEAT BALANCE. Peter J. Lamb. Cooperative Institute for Mesoscale Meteorological Studies RADIATION IN THE TROPICAL ATMOSPHERE and the SAHEL SURFACE HEAT BALANCE by Peter J. Lamb Cooperative Institute for Mesoscale Meteorological Studies and School of Meteorology The University of Oklahoma

More information

Corso di Fisica Te T cnica Ambientale Solar Radiation

Corso di Fisica Te T cnica Ambientale Solar Radiation Solar Radiation Solar radiation i The Sun The Sun is the primary natural energy source for our planet. It has a diameter D = 1.39x10 6 km and a mass M = 1.989x10 30 kg and it is constituted by 1/3 of He

More information

meteonorm Global Meteorological Database

meteonorm Global Meteorological Database meteonorm Global Meteorological Database Version 7 Software and Data for Engineers, Planners and Education The Meteorological Reference for Solar Energy Applications, Building Design, Heating & Cooling

More information

Cooling Load Calculation

Cooling Load Calculation for A Probabilistic Approach Taperit Tongshoob 1 Chirdpun Vitooraporn 2 Cooling Load Calculation Abstract 1 Ph.D Student 2 Lecturer at Building Technology Environment Laboratory, Mechanical Engineering

More information

Solar Energy Utilisation in Buildings

Solar Energy Utilisation in Buildings Solar Energy Utilisation in Buildings P. Karava, PhD Assistant professor Department of Civil and Environmental Engineering University of Western Ontario 2 Modern Buildings Change in architectural style

More information

HEATING OF DOMESTIC OUTDOOR SWIMMING POOLS

HEATING OF DOMESTIC OUTDOOR SWIMMING POOLS HEATING OF DOMESTIC OUTDOOR SWIMMING POOLS INTRODUCTION 1. There are no general EU regulations and standards for outdoor swimming pool heating. Local regulations in the member countries are covering most

More information

SOLAR ENERGY How much strikes the earth? How much can my building get? When is it too much?

SOLAR ENERGY How much strikes the earth? How much can my building get? When is it too much? SOLAR ENERGY How much strikes the earth? How much can my building get? When is it too much? The sun: friend of foe? Drawing by Le Corbusier ENGS 44 Sustainable Design Benoit Cushman-Roisin 14 April 2015

More information

Geography affects climate.

Geography affects climate. KEY CONCEPT Climate is a long-term weather pattern. BEFORE, you learned The Sun s energy heats Earth s surface unevenly The atmosphere s temperature changes with altitude Oceans affect wind flow NOW, you

More information

CHAPTER 5 Lectures 10 & 11 Air Temperature and Air Temperature Cycles

CHAPTER 5 Lectures 10 & 11 Air Temperature and Air Temperature Cycles CHAPTER 5 Lectures 10 & 11 Air Temperature and Air Temperature Cycles I. Air Temperature: Five important factors influence air temperature: A. Insolation B. Latitude C. Surface types D. Coastal vs. interior

More information

Comparing Air Cooler Ratings Part 1: Not All Rating Methods are Created Equal

Comparing Air Cooler Ratings Part 1: Not All Rating Methods are Created Equal Technical Bulletin By Bruce I. Nelson, P.E., President, Colmac Coil Manufacturing, Inc. Comparing Air Cooler Ratings Part 1: Not All Rating Methods are Created Equal SUMMARY Refrigeration air coolers (evaporators)

More information

UNIT 6a TEST REVIEW. 1. A weather instrument is shown below.

UNIT 6a TEST REVIEW. 1. A weather instrument is shown below. UNIT 6a TEST REVIEW 1. A weather instrument is shown below. Which weather variable is measured by this instrument? 1) wind speed 3) cloud cover 2) precipitation 4) air pressure 2. Which weather station

More information

A NEW DESICCANT EVAPORATIVE COOLING CYCLE FOR SOLAR AIR CONDITIONING AND HOT WATER HEATING

A NEW DESICCANT EVAPORATIVE COOLING CYCLE FOR SOLAR AIR CONDITIONING AND HOT WATER HEATING A NEW DESICCANT EVAPORATIVE COOLING CYCLE FOR SOLAR AIR CONDITIONING AND HOT WATER HEATING John Archibald American Solar Roofing Company 8703 Chippendale Court Annandale, Va. 22003 e-mail: jarchibald@americansolar.com

More information

Carnegie Mellon University School of Architecture, Department of Mechanical Engineering Center for Building Performance and Diagnostics

Carnegie Mellon University School of Architecture, Department of Mechanical Engineering Center for Building Performance and Diagnostics Carnegie Mellon University School of Architecture, Department of Mechanical Engineering Center for Building Performance and Diagnostics A Presentation of Work in Progress 4 October 2006 in the Intelligent

More information

Humid Air. Water vapor in air. Trace Glasses 1% Argon (A) Water vapor (H 2

Humid Air. Water vapor in air. Trace Glasses 1% Argon (A) Water vapor (H 2 Humid Air Water vapor in air Oxygen 21% Trace Glasses 1% Argon (A) Water vapor (H 2 O) Carbon dioxide (CO 2 ) Neon (Ne) Helium (He) Krypton (Kr) Hydrogen (H) Ozone (O 3 ) Nitrogen 78% Humid Air Water vapor

More information

Global Seasonal Phase Lag between Solar Heating and Surface Temperature

Global Seasonal Phase Lag between Solar Heating and Surface Temperature Global Seasonal Phase Lag between Solar Heating and Surface Temperature Summer REU Program Professor Tom Witten By Abstract There is a seasonal phase lag between solar heating from the sun and the surface

More information

Adaptive strategies for office spaces in the UK climate

Adaptive strategies for office spaces in the UK climate International Conference Passive and Low Energy Cooling 631 Adaptive strategies for office spaces in the UK climate I. Gallou Environment & Energy Studies Programme, Architectural Association Graduate

More information

ANSI/ASHRAE Standard 140-2004 Building Thermal Envelope and Fabric Load Tests

ANSI/ASHRAE Standard 140-2004 Building Thermal Envelope and Fabric Load Tests ANSI/ASHRAE Standard 140-2004 Building Thermal Envelope and Fabric Load Tests DesignBuilder Version 1.2.0 (incorporating EnergyPlus version 1.3.0) - June 2006 1.0 Purpose The ANSI/ASHRAE Standard 140-2004

More information

The Surface Energy Budget

The Surface Energy Budget The Surface Energy Budget The radiation (R) budget Shortwave (solar) Radiation Longwave Radiation R SW R SW α α = surface albedo R LW εσt 4 ε = emissivity σ = Stefan-Boltzman constant T = temperature Subsurface

More information

Empirical study of the temporal variation of a tropical surface temperature on hourly time integration

Empirical study of the temporal variation of a tropical surface temperature on hourly time integration Global Advanced Research Journal of Physical and Applied Sciences Vol. 4 (1) pp. 051-056, September, 2015 Available online http://www.garj.org/garjpas/index.htm Copyright 2015 Global Advanced Research

More information

ENGINEERING WEATHER DATA

ENGINEERING WEATHER DATA INTRODUCTION ENGINEERING WEATHER DATA Background. The data in this handbook were compiled by the Air Force Combat Climatology Center (AFCCC) at the request of the Air Force Civil Engineer Support Agency

More information

3-D Modeller Rendered Visualisations

3-D Modeller Rendered Visualisations Recognised energy Dynamic Simulation Modelling (DSM) software DesignBuilder is a user interface to the EnergyPlus DSM. EnergyPlus builds on the most popular features and capabilities of BLAST and DOE-2

More information

Radiation Transfer in Environmental Science

Radiation Transfer in Environmental Science Radiation Transfer in Environmental Science with emphasis on aquatic and vegetation canopy media Autumn 2008 Prof. Emmanuel Boss, Dr. Eyal Rotenberg Introduction Radiation in Environmental sciences Most

More information

Analysis of data centre cooling energy efficiency

Analysis of data centre cooling energy efficiency Analysis of data centre cooling energy efficiency An analysis of the distribution of energy overheads in the data centre and the relationship between economiser hours and chiller efficiency Liam Newcombe

More information

ENERGY AUDIT. Project : Industrial building United Arab Emirates (Case study) Contact person (DERBIGUM):

ENERGY AUDIT. Project : Industrial building United Arab Emirates (Case study) Contact person (DERBIGUM): ENERGY AUDIT Project : Industrial building United Arab Emirates (Case study) Contact person (DERBIGUM): Leonard Fernandes DERBIGUM project reference : UAE -2014 - EA 103 Author : Daniel Heffinck (DERBIGUM)

More information

Clouds and the Energy Cycle

Clouds and the Energy Cycle August 1999 NF-207 The Earth Science Enterprise Series These articles discuss Earth's many dynamic processes and their interactions Clouds and the Energy Cycle he study of clouds, where they occur, and

More information

Influence of Solar Radiation Models in the Calibration of Building Simulation Models

Influence of Solar Radiation Models in the Calibration of Building Simulation Models Influence of Solar Radiation Models in the Calibration of Building Simulation Models J.K. Copper, A.B. Sproul 1 1 School of Photovoltaics and Renewable Energy Engineering, University of New South Wales,

More information

Total Heat Versus Sensible Heat Evaporator Selection Methods & Application

Total Heat Versus Sensible Heat Evaporator Selection Methods & Application Total Heat Versus Sensible Heat Evaporator Selection Methods & Application Scope The purpose of this paper is to provide specifying engineers, purchasers and users of evaporators in industrial refrigeration

More information

Chapter Overview. Seasons. Earth s Seasons. Distribution of Solar Energy. Solar Energy on Earth. CHAPTER 6 Air-Sea Interaction

Chapter Overview. Seasons. Earth s Seasons. Distribution of Solar Energy. Solar Energy on Earth. CHAPTER 6 Air-Sea Interaction Chapter Overview CHAPTER 6 Air-Sea Interaction The atmosphere and the ocean are one independent system. Earth has seasons because of the tilt on its axis. There are three major wind belts in each hemisphere.

More information

Chapter 3.4: HVAC & Refrigeration System

Chapter 3.4: HVAC & Refrigeration System Chapter 3.4: HVAC & Refrigeration System Part I: Objective type questions and answers 1. One ton of refrigeration (TR) is equal to. a) Kcal/h b) 3.51 kw c) 120oo BTU/h d) all 2. The driving force for refrigeration

More information

APPENDIX D: SOLAR RADIATION

APPENDIX D: SOLAR RADIATION APPENDIX D: SOLAR RADIATION The sun is the source of most energy on the earth and is a primary factor in determining the thermal environment of a locality. It is important for engineers to have a working

More information

Dispelling the Solar Myth - Evacuated Tube versus Flat Plate Panels. W illiam Comerford Sales Manager Ireland Kingspan Renewables Ltd.

Dispelling the Solar Myth - Evacuated Tube versus Flat Plate Panels. W illiam Comerford Sales Manager Ireland Kingspan Renewables Ltd. Dispelling the Solar Myth - Evacuated Tube versus Flat Plate Panels W illiam Comerford Sales Manager Ireland Kingspan Renewables Ltd. 1 The Kingspan Group Energy independent buildings for a sustainable

More information

Building Energy Systems. - HVAC: Heating, Distribution -

Building Energy Systems. - HVAC: Heating, Distribution - * Some of the images used in these slides are taken from the internet for instructional purposes only Building Energy Systems - HVAC: Heating, Distribution - Bryan Eisenhower Associate Director Center

More information

Overview. What is EMR? Electromagnetic Radiation (EMR) LA502 Special Studies Remote Sensing

Overview. What is EMR? Electromagnetic Radiation (EMR) LA502 Special Studies Remote Sensing LA502 Special Studies Remote Sensing Electromagnetic Radiation (EMR) Dr. Ragab Khalil Department of Landscape Architecture Faculty of Environmental Design King AbdulAziz University Room 103 Overview What

More information

Temperature and Humidity

Temperature and Humidity Temperature and Humidity Overview Water vapor is a very important gas in the atmosphere and can influence many things like condensation and the formation of clouds and rain, as well as how hot or cold

More information

DEVELOPMENT OF AN OPEN SOURCE HOURLY BUILDING ENERGY MODELING SOFTWARE TOOL

DEVELOPMENT OF AN OPEN SOURCE HOURLY BUILDING ENERGY MODELING SOFTWARE TOOL DEVELOPMENT OF AN OPEN SOURCE HOURLY BUILDING ENERGY MODELING SOFTWARE TOOL Brittany Hanam, MASc, EIT RDH Building Engineering Ltd. Vancouver, BC John Straube, PhD, P.Eng. Building Engineering Group, Civil

More information

PROTOCOL FOR BUILDING ENERGY ANALYSIS SOFTWARE For Class 3, 5, 6, 7, 8 and 9 buildings

PROTOCOL FOR BUILDING ENERGY ANALYSIS SOFTWARE For Class 3, 5, 6, 7, 8 and 9 buildings PROTOCOL FOR BUILDING ENERGY ANALYSIS SOFTWARE For Class 3, 5, 6, 7, 8 and 9 buildings Version 2006.1 AUSTRALIAN BUILDING CODES BOARD JANUARY 2006 TABLE OF CONTENTS Foreword 1. Scope 2. Purpose and context

More information

SIMULATION OF RADIANT COOLING PERFORMANCE WITH

SIMULATION OF RADIANT COOLING PERFORMANCE WITH SUMMARY REPORT MAY 2008 SIMULATION OF RADIANT COOLING PERFORMANCE WITH EVAPORATIVE COOLING SOURCES Timothy Moore Center for the Built Environment (CBE) University of California, Berkeley May 2008 EXECUTIVE

More information

Forecaster comments to the ORTECH Report

Forecaster comments to the ORTECH Report Forecaster comments to the ORTECH Report The Alberta Forecasting Pilot Project was truly a pioneering and landmark effort in the assessment of wind power production forecast performance in North America.

More information

FACTSHEET Assessing the Feasibility of Using Solar-Thermal Systems for Your Agricultural or Agri-Food Operation

FACTSHEET Assessing the Feasibility of Using Solar-Thermal Systems for Your Agricultural or Agri-Food Operation FACTSHEET Assessing the Feasibility of Using Solar-Thermal Systems for Your Agricultural or Agri-Food Operation Solar-thermal systems collect the sun's energy and convert it into heat. This energy can

More information

A Novel Method for Predicting the Power Output of Distributed Renewable Energy Resources

A Novel Method for Predicting the Power Output of Distributed Renewable Energy Resources A Novel Method for Predicting the Power Output of Distributed Renewable Energy Resources Aris-Athanasios Panagopoulos1 Joint work with Georgios Chalkiadakis2 and Eftichios Koutroulis2 ( Predicting the

More information

REDUCING UNCERTAINTY IN SOLAR ENERGY ESTIMATES

REDUCING UNCERTAINTY IN SOLAR ENERGY ESTIMATES REDUCING UNCERTAINTY IN SOLAR ENERGY ESTIMATES Mitigating Energy Risk through On-Site Monitoring Marie Schnitzer, Vice President of Consulting Services Christopher Thuman, Senior Meteorologist Peter Johnson,

More information

2 Absorbing Solar Energy

2 Absorbing Solar Energy 2 Absorbing Solar Energy 2.1 Air Mass and the Solar Spectrum Now that we have introduced the solar cell, it is time to introduce the source of the energy the sun. The sun has many properties that could

More information

THE PSYCHROMETRIC CHART AND ITS USE

THE PSYCHROMETRIC CHART AND ITS USE Service Application Manual SAM Chapter 630-16 Section 3A THE PSYCHROMETRIC CHART AND ITS USE Psychrometry is an impressive word which is defined as the measurement of the moisture content of air. In broader

More information

Greenhouse Glazing Effects on Heat Transfer for Winter Heating and Summer Cooling

Greenhouse Glazing Effects on Heat Transfer for Winter Heating and Summer Cooling Greenhouse Glazing Effects on Heat Transfer for Winter Heating and Summer Cooling David R. Mears, Ph.D. Bioresource Engineering Department of Plant Biology and Pathology Rutgers University 20 Ag Extension

More information

Federation of European Heating, Ventilation and Air-conditioning Associations

Federation of European Heating, Ventilation and Air-conditioning Associations Federation of European Heating, Ventilation and Air-conditioning Associations Address: Rue Washington 40 1050 Brussels Belgium www.rehva.eu info@rehva.eu Tel: +32 2 514 11 71 Fax: +32 2 512 90 62 REHVA

More information

Yijun Gao, Wei Wu, Zongwei Han, Xianting Li *

Yijun Gao, Wei Wu, Zongwei Han, Xianting Li * Study on the performance of air conditioning system combining heat pipe and vapor compression based on ground source energy-bus for commercial buildings in north China Yijun Gao, Wei Wu, Zongwei Han, Xianting

More information

VENTILATIVE COOLING EBC ANNEX 62 PER HEISELBERG DEPARTMENT OF CIVIL ENGINEERING

VENTILATIVE COOLING EBC ANNEX 62 PER HEISELBERG DEPARTMENT OF CIVIL ENGINEERING VENTILATIVE COOLING EBC ANNEX 62 PER HEISELBERG DEFINITION OF VENTILATIVE COOLING VENTILATIVE COOLING IS APPLICATION (DISTRIBUTION IN TIME AND SPACE) OF VENTILATION AIR FLOW TO REDUCE COOLING LOADS IN

More information

8.5 Comparing Canadian Climates (Lab)

8.5 Comparing Canadian Climates (Lab) These 3 climate graphs and tables of data show average temperatures and precipitation for each month in Victoria, Winnipeg and Whitehorse: Figure 1.1 Month J F M A M J J A S O N D Year Precipitation 139

More information

Full credit for this chapter to Prof. Leonard Bachman of the University of Houston

Full credit for this chapter to Prof. Leonard Bachman of the University of Houston Chapter 6: SOLAR GEOMETRY Full credit for this chapter to Prof. Leonard Bachman of the University of Houston SOLAR GEOMETRY AS A DETERMINING FACTOR OF HEAT GAIN, SHADING AND THE POTENTIAL OF DAYLIGHT PENETRATION...

More information

Radiant Heating and Cooling Systems BY KWANG WOO KIM, ARCH.D., MEMBER ASHRAE; BJARNE W. OLESEN, PH.D., FELLOW ASHRAE

Radiant Heating and Cooling Systems BY KWANG WOO KIM, ARCH.D., MEMBER ASHRAE; BJARNE W. OLESEN, PH.D., FELLOW ASHRAE TECHNICAL FEATURE Fundamentals at Work This article was published in ASHRAE Journal, February 2015. Copyright 2015 ASHRAE. Posted at www.ashrae.org. This article may not be copied and/or distributed electronically

More information

SOLAR RADIATION AND YIELD. Alessandro Massi Pavan

SOLAR RADIATION AND YIELD. Alessandro Massi Pavan SOLAR RADIATION AND YIELD Alessandro Massi Pavan Sesto Val Pusteria June 22 nd 26 th, 2015 DEFINITIONS Solar radiation: general meaning Irradiation [Wh/m 2 ]: energy received per unit area Irradiance [W/m

More information

MCQ - ENERGY and CLIMATE

MCQ - ENERGY and CLIMATE 1 MCQ - ENERGY and CLIMATE 1. The volume of a given mass of water at a temperature of T 1 is V 1. The volume increases to V 2 at temperature T 2. The coefficient of volume expansion of water may be calculated

More information

FIRST RADIANT COOLED COMMERCIAL BUILDING IN INDIA CRITICAL ANALYSIS OF ENERGY, COMFORT AND COST

FIRST RADIANT COOLED COMMERCIAL BUILDING IN INDIA CRITICAL ANALYSIS OF ENERGY, COMFORT AND COST FIRST RADIANT COOLED COMMERCIAL BUILDING IN INDIA CRITICAL ANALYSIS OF ENERGY, COMFORT AND COST Guruprakash Sastry, Senior Manager Green Initiatives Infosys Limited, Bangalore, INDIA ABSTRACT Radiation

More information

BEST 3, Atlanta, April 2012 Grahame E. Maisey, P.E.

BEST 3, Atlanta, April 2012 Grahame E. Maisey, P.E. A Methodology to Develop a Sustainable, High Performance Building Envelope BEST 3, Atlanta, April 2012 Grahame E. Maisey, P.E. We re Going To Reveal New Sustainable Truths and Expose Old Bogus Truths We

More information

National Building Code of Canada 2010

National Building Code of Canada 2010 National Building Code of Canada 2010 Emergency Change Issued by the Canadian Commission on Building and Fire Codes The table that follows lists two emergency changes that apply to the National Building

More information

ENERGY PERFORMANCE MODELLING AND HEAT RECOVERY UNIT EFFICIENCY ASSESSMENT OF AN OFFICE BUILDING

ENERGY PERFORMANCE MODELLING AND HEAT RECOVERY UNIT EFFICIENCY ASSESSMENT OF AN OFFICE BUILDING THERMAL SCIENCE: Year 2015, Vol. 19, No. 3, pp. 865-880 865 ENERGY PERFORMANCE MODELLING AND HEAT RECOVERY UNIT EFFICIENCY ASSESSMENT OF AN OFFICE BUILDING by Norbert L. HARMATI a*, Radomir J. FOLI] a,

More information

Building envelope and heat capacity: re-discovering the thermal mass for winter energy saving

Building envelope and heat capacity: re-discovering the thermal mass for winter energy saving 346 2nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and Building envelope and heat capacity: re-discovering the thermal mass for winter energy saving S. Ferrari Politecnico

More information

COOLING AND HEATING OF BUILDINGS BY ACTIVATING THEIR THERMAL MASS WITH EMBEDDED HYDRONIC PIPE SYSTEMS -

COOLING AND HEATING OF BUILDINGS BY ACTIVATING THEIR THERMAL MASS WITH EMBEDDED HYDRONIC PIPE SYSTEMS - pcoolingandheating COOLING AND HEATING OF BUILDINGS BY ACTIVATING THEIR THERMAL MASS WITH EMBEDDED HYDRONIC PIPE SYSTEMS - Bjarne W. Olesen, Ph.D. D. F. Liedelt "Velta" Summary Due to intensive use of

More information

Drury B. Crawley U.S. Department of Energy Washington, DC 20585 USA

Drury B. Crawley U.S. Department of Energy Washington, DC 20585 USA TESTING AND VALIDATION OF A NEW BUILDING ENERGY SIMULATION PROGRAM Michael J. Witte, Robert H. Henninger, and Jason Glazer GARD Analytics, Inc. Park Ridge, IL 668 USA Drury B. Crawley U.S. Department of

More information

Measuring The Right Thing For Humidity Control It s the Dew Point Stupid!

Measuring The Right Thing For Humidity Control It s the Dew Point Stupid! Page 1 of 6 Measuring The Right Thing For Humidity Control It s the Dew Point Stupid! By Mike Schell, AirTest Technologies Corp. A version of this article appeared in the June 2004 edition of Indoor Air

More information