1 EnergyPro Building Energy Analysis Hotel Building
2 EnergyPro Building Energy Analysis for a hotel building Project Scope The purpose of the EnergyPro model was to evaluate the energy usage of a building installed with a VRFZ solution compared to that of a packaged terminal heat pump (PTHP) system, a water-source heat pump (WSHP) system, and a hot-water/chilled-water four-pipe fan coil system. The selected systems were then compared with the solutions across the country:, GA,, FL,, MA, New York City, NY,, IL,, TX, Los Angeles, CA, and, WA. The goal of the energy model was to understand how HVAC systems compared with standard HVAC systems in various climate zones. Building Description The simulated building chosen was a 100,000 square foot, four-story, rectangularshaped hotel. The hotel modeled was a 4 story select service type containing 123 guestrooms, entrance lobby, meeting rooms, exercise area, and back of house services. The main section of the building runs east and west with two wings on the north end; there is a great deal of exterior exposure on all sides. The building was modeled in each of the cities listed in the previous paragraph. Building specifications such as floor plans, R-Values, U-Values, etc., followed what was typical for construction values in each of the areas specified. The building was modeled in EnergyPro, and four simulations were created: a heatrecovery system, a packaged terminal heat pump system, a boiler and chiller serving four-pipe fan coil units, and a water-source heat pump system. The non-hvac energy usage such as lighting, plug loads, etc., were the same in all models (see the Engineering Assumptions Table for specifics). All utility rates used in the savings analysis were obtained from The rates are provided in the Utility Rate Summary Table. Mitsubishi Electric Design Description For the simulated hotel, a single ducted unit was used in each guest room. For larger zones in the simulated hotel s first floor such as the lobby and meeting rooms, a combination of ducted units and ceiling cassettes were used. Ten R2-Series heat recovery outdoor units served the building, with two outdoor units serving each of the three guest room floors. The outside air load was applied directly to each of the indoor units at the zone level. PTHP Design Description The hotel was modeled with a PTHP system with auxiliary electric heat in each room. The PTHP s were modeled with an EER (Energy Efficiency Ratio) of 10.7 and an HSPF (Heat Seasonal Performance Factor) of 7.5. The common areas were conditioned using PTHP s sized and spaced throughout the zones as needed to maintain room temperature. The outside air was conditioned by the PTHPs. Water-source Heat Pump (WSHP) Design Description To provide conditioning to the simulated hotel, water-source heat pumps with a 15.4 EER and a 4.7 COP (Coefficient of Performance) were modeled. The water-source heat pumps were served by a two-speed cooling tower and a pump to circulate the water. A supplemental condensing boiler was attached to the condenser water loop to provide heat when the cooling tower could not maintain the water-loop temperature. The outside air was conditioned by the water-source heat pumps. A single heat pump was provided to serve each of the guest rooms. The common areas were conditioned using WSHP s sized and spaced throughout the zones as needed to maintain room temperature. Four-pipe Design Description To provide conditioning to the simulated hotel, a chiller and boiler serving four-pipe fan coil units were modeled. A water-cooled chiller with an efficiency of 0.72 kw/ton was used. The chiller was served by a two-speed cooling tower, and each was served by a set of pumps to circulate condenser water and chilled water. A condensing boiler with an efficiency of 91.5% provided hot water to the fan coil units. The outside air was conditioned by the fan coil units. A single fan coil unit was provided to serve each of the guest rooms. The common areas were conditioned using fan coil units sized and spaced throughout the zones as needed to maintain room temperature.
3 Total Energy Cost Savings vs. PTHP vs. WSHP vs. Four-pipe Location 0% 3.5% 7% 10.5% 14% 17.5% 21% 24.5% 28% 31.5% 35% 38.5% Total Energy Cost Savings (%) (Reference Table 3 for more details) LEED NC 2.2 and VRFZ Systems are helpful in obtaining points for LEED (Leadership in Energy and Environmental Design) Energy and Atmosphere credit 1. The U.S. Green Building Council (USGBC) developed the LEED Green Building Rating System as a voluntary, consensus-based national standard for developing high-performance, sustainable buildings. Building energy savings can be demonstrated by performing a building energy model using the EnergyPro software available from EnergySoft, LLC. and comparing the building design with a baseline building as defined by ASHRAE std EnergyPro is approved by the USGBC for EAc1 calculations. As shown below, the percentage of total energy savings relates directly to LEED credits. LEED Points based on Total Energy Savings (EA Credit 1) New Buildings Existing Building Renovations Points 10.5% 3.5% 1 14% 7% % 10.5% 3 21% 14% % 17.5% 5 28% 21% % 24.5% 7 35% 28% % 31.5% 9 42% 35% 10 The graphs on the following page show the percentage savings of VRFZ over the ASHRAE std baseline which is the PTHP system as well as other system types. Quality and reliability are significantly more important to hotel design professionals than other mechanical product-related factors. High importance is also placed on ease of use in hotel rooms by guests, operating efficiency and operating sound levels. - according to a recent study conducted by Clear Seas Research.
4 The most common challenges in providing a comfortable hotel environment include cost, sound control and humidity. The most frequent complaint regarding comfort focuses on the temperature being too hot or too cold. - according to a recent study conducted by Clear Seas Research. $200,000 Total Energy Cost Comparison for and Packaged Terminal Heat Pump $175,000 Total Energy Cost ($) $150,000 $125,000 $100,000 PTHP $75,000 $50,000 $25,000 $0 Location 32% 13% 40% 36% 38% 22% 20% 37% as compared to PTHP A PTHP system is the baseline defined by ASHRAE std for this building size and type. Energy usage was calculated for the buildings using both systems. On average, the system saw a total energy cost savings of 30% when compared with the PTHP systems, and a 41% average savings when comparing HVAC energy cost. The savings varied greatly based upon the modeled location and the applied local utility rates. Based on the average energy cost savings from the models, future projects would meet the LEED EA credit 1 prerequisite and qualify for six LEED points. Specific results for each area have been detailed in the Energy Usage Summary (Tables 3, 4).
5 Total Energy Cost ($) $200,000 $175,000 $150,000 $125,000 $100,000 $75,000 $50,000 $25,000 $0 Location Total Cost Comparison for and Water Source Heat Pump 21% 22% 11% 15% 8% 20% 28% 14% WSHP as compared to WSHP WSHP systems have recently become a popular choice for hotels needing to replace outdated HVAC systems. Energy usage was calculated for the buildings using both systems. The total energy cost savings realized with the system was 17% on average compared to a WSHP system. When comparing the energy cost used by the HVAC systems alone, was 25% less on average. The energy use is detailed in the Energy Usage Summary (Tables 3, 4). Total Energy Cost ($) $200,000 $175,000 $150,000 $125,000 $100,000 $75,000 $50,000 $25,000 $0 Location Total Energy Cost Comparison for and Four-pipe 25% 22% 18% 16% 17% 20% 25% 22% Four-pipe as compared to Four-pipe A four-pipe fan coil unit system is a standard HVAC package used in many building types. Energy usage was calculated for the buildings using both systems. On average, the total energy cost savings realized with the system was 21% when compared to a four-pipe fan coil unit system and a 30% average savings when comparing HVAC energy cost. Savings were fairly constant across all locations. Savings for each location are detailed in the Energy Usage Summary (Tables 3, 4).
6 Engineering Assumptions Weather Profile based on locations shown in the ASHRAE Design Temperature table. Item Design Assumption Building Area As defined by the provided plans Glass selection Double Thermal Break Clear U-Value: SHGC: Walls Construction: Wood frame Insulation: R-19 Total Assembly U-Value: Roof Construction: R-19 Roof over Metal Deck Insulation: R-19 Total Assembly U-Value: Reflectivity: 0.7 Energy savings is the most important cost-related factor for the hotel community when it comes to a comfortable internal environment, followed by prod- uct life and maintenance costs. - according to a recent study by Clear Seas Research. VRFZ system PTHP HVAC system Water Source Heat Pump HVAC system 4-Pipe Fan Coil Unit HVAC system A R2-Series heat recovery system with ducted and wall-mounted units. Packaged Terminal Heat Pump (PTHP) with auxiliary electric strip heat EER, 7.5 HSPF Water source heat pumps served by a 2-speed cooling tower and a 91.5 % efficient supplemental boiler, The heat pumps have an efficiency of 15.4 EER and a COP of 4.7. All pumps were sized per ASHRAE recommendations. Fan Coil Units served by a 91.5% efficient boiler, a water cooled screw chiller with an efficiency of 0.72kw/ton and a 2-speed cooling tower. All pumps were sized per ASHRAE recommendations. Miscellaneous Loads Hotel: 1.5 Watts/ft 2 Schedules Utility Rates Standard ASHRAE 90.1 Profile and Operation Schedules See Utility Rate Summary Table Table 1. Utility Rate Summary Electric ($/KWH) Gas ($/Therm) Table 2. ASHRAE Design Temperature Summer DB 0.40% Summer MWB 0.40% Winter DB 99.6%
7 Table 3. Total Energy Usage Summary Total KWH 620, , , , , , , ,896 Total Therm Total MMBTU 2,117 2,584 2,137 2,119 2,335 2,263 1,827 1,874 Total Cost $69,254 $88,852 $110,761 $122,578 $74,800 $92,362 $80,163 $42,539 Total KWH 913, ,571 1,039, ,563 1,099, , , ,813 PTHP Total Therm Total MMBTU 3,118 2,959 3,548 3,294 3,755 2,907 2,279 2,984 Total Cost $101,994 $101,735 $183,909 $190,501 $120,302 $118,697 $49,974 $67,720 Total KWH 783, , , , , , , ,797 WSHP Total Therm , Total MMBTU 2,692 3,329 2,458 2,524 2,607 2,849 2,532 2,179 Total Cost $87,760 $114,450 $124,375 $143,369 $81,002 $115,910 $111,094 $49,239 Total KWH 726, , , , , , , ,528 Four-pipe MMBTU Savings Cost Savings Total Therm 8, ,453 14,243 17,546 5,773 1,230 14,174 Total MMBTU 3,328 3,334 3,831 3,624 3,949 3,272 2,543 3,130 Total Cost $92,627 $114,627 $134,398 $145,702 $89,806 $116,134 $107,590 $54,587 CM vs. PTHP 32% 13% 40% 36% 38% 22% 20% 37% CM vs. WSHP 21% 22% 13% 16% 10% 21% 28% 14% CM vs. Four-pipe 36% 22% 44% 42% 41% 31% 28% 40% CM vs. PTHP 32% 13% 40% 36% 38% 22% 20% 37% CM vs. WSHP 21% 22% 11% 15% 8% 20% 28% 14% CM vs. Four-pipe 25% 22% 18% 16% 17% 20% 25% 22% Table 4. HVAC Only Energy Usage Summary Total KWH 375, , , , , , , ,146 Total Therm Total MMBTU 1,282 1,749 1,301 1,284 1,499 1, ,039 Total Cost $41,916 $60,119 $67,441 $74,240 $48,025 $58,244 $43,500 $23,571 Total KWH 668, , , , , , , ,063 PTHP Total Therm Total MMBTU 2,282 2,123 2,712 2,458 2,919 2,072 1,443 2,148 Total Cost $74,656 $73,002 $140,588 $142,163 $93,527 $84,579 $63,311 $48,752 Total KWH 538, , , , , , , ,047 WSHP Total Therm , Total MMBTU 1,857 2,493 1,623 1,689 1,772 2,013 1,697 1,343 Total Cost $60,422 $85,716 $81,055 $95,031 $54,227 $81,793 $74,436 $30,271 Total KWH 481, , , , , , , ,778 Four-pipe MMBTU Savings Cost Savings Total Therm 8, ,453 14,243 17,546 5,773 1,230 14,174 Total MMBTU 2,493 2,498 2,995 2,788 3,113 2,436 1,708 2,295 Total Cost $65,289 $85,534 $91,078 $97,364 $63,031 $82,016 $70,927 $35,619 CM vs. PTHP 44% 18% 52% 48% 49% 31% 31% 52% CM vs. WSHP 31% 30% 20% 24% 15% 29% 42% 23% CM vs. Four-pipe 49% 30% 57% 54% 52% 41% 42% 55% CM vs. PTHP 44% 18% 52% 48% 49% 31% 31% 52% CM vs. WSHP 31% 30% 17% 22% 11% 29% 42% 22% CM vs. Four-pipe 36% 30% 26% 24% 24% 29% 39% 34% * is abbreviated as CM in the above tables.
8 Advantages of over Comparable Systems The EnergyPro model demonstrated that systems offer reduced energy costs because of part-load efficiency and the ability to simultaneously cool and heat. R2-Series heat recovery systems can simultaneously cool and heat different zones, which allows energy to be recovered from one zone and used in another, resulting in a huge increase in efficiency and energy savings over all of the compared systems. There are some major areas in which the system offers an advantage over other systems: 1. Initial Cost: systems consist of an outdoor unit, an indoor unit in each zone, a BC controller (R2-Series only), refrigerant piping, and a very simple controls system. A four-pipe fan coil unit system includes a boiler, chiller, fan coil units, pumps, hot water piping, chilled water piping, a controls system, etc. A water-source heat pump system includes a cooling tower, supplemental boiler, condenser water piping, condenser water pumps, heat pumps, a controls system, etc. The reduced equipment required and ease of installation makes the a superior first cost solution. 2. Comfort: One of the biggest advantages that CITY MULTI VRFZ solutions have over other systems is the increased comfort level for the occupants. VRFZ technology allows indoor units to operate at the precise level necessary to maintain room temperature which, when combined with the powerful controls system, allows the occupants to experience consistent comfort throughout the day. 3. Quiet Operation: indoor and outdoor units operate at low sound levels; for example, a 20-ton outdoor unit operating at high speed has a sound level of 63 db(a). Some indoor models have an operating sound level in the low 20 db(a)s range, depending on fan speed and duct design. For contrast, the sound level for normal conversation is approximately 60 db(a). 4. Installation Space: systems do not require a mechanical room. Outdoor units can be installed outside either on grade or the roof and piped directly to indoor units, eliminating the need for pumps. Depending on the type of indoor unit, they can be installed in plenum spaces, on walls, or in the ceiling. Refrigerant piping is routed to the BC controller, also located in the plenum space, and then to the outdoor unit. 5. Installation Time: Because there are fewer components in a system, the time it takes for installation is much shorter than for other systems. An indoor unit can be mounted and piped from the BC controller in hours. 6. Flexibility: The zoning capabilities of systems allow for one indoor unit to be taken offline without affecting other indoor units. An outdoor unit can also be shut down and affect only a few zones. However with other systems if an air-handling unit should fail, or a component of the central mechanical system should fail (chiller, cooling tower or pumps) a large portion, if not all, building conditioning would be lost. 7. Versatility: systems offer a choice of inside air handlers: ducted, wall-mounted, ceiling-mounted, and floor-mounted. Many other systems only offer limited indoor unit selections. 8. Efficiency: R2-Series systems have the ability to recover energy when simultaneously cooling and heating, thereby reducing energy and increasing operating efficiency. Variable refrigerant flow zoning technology also allows to automatically adjust to changing loads in each zone, maintaining the required temperature levels and operating at a lower cost. 9. Maintenance: systems require significantly less maintenance; typically only requiring filter changes. systems have a life expectancy of 15 to 20 years. Water-source heat pump systems require regular maintenance to maintain the compressor and keep the system functioning properly. Form No. EPBROHTLBLD-7-09 V2 For more information visit Please recycle. Mitsubishi Electric Advanced Products Division 3400 Lawrenceville Suwanee Road Suwanee, GA Phone: Fax: Mitsubishi Electric & Electronics USA, Inc. is a registered trademark of Mitsubishi Electric. The three-diamond logo is a registered logo of Mitsubishi Electric Corporation.