ERV HRV. Jason Morosko UltimateAir Inc Athens, Ohio

Transcription

1 ERV HRV Jason Morosko UltimateAir Inc Athens, Ohio

2 About Me: Jason Morosko, MSME, Certified Passive House Consultant Manufacturer/Designer of energy recovery ventilation equipment High performance home design consultant, specialty in envelop/mechanicals Finishing i a passive house Oct 2011

3 North American CLIMATES Very cold Marine Mixed and humid Mixed and dry Hot and Humid Hot and Dry

4 DISCUSSION HRV ERV Heat Recovery Ventilator recovers sensible (heat only) energy Energy Recovery Ventilator recovers sensible and latent (moisture) energy HRV s transfer only sensible heat. The apparent sensible effectiveness is the difference the incoming air temperature will be relative to the leaving air temperature. ERV s transfer sensible heat (same as hrv s) plus moisture. An ERV will move a percentage of the moisture (LPC latent performance coefficient) from the higher specific humidity air stream to the lower specific humidity air stream (specific humidity same as humidity ratio in the following slides). So is your HRV or ERV humidifying or dehumidifying your HOUSE? That s a tricky question.

5 RELATIVE HUMIDITY Why do I feel hot, and you feel cold? [Same inside temperature and humidity] Perspiration! skin relies on the air to get rid of moisture. The process of sweating is your body's attempt to keep cool and maintain its current temperature. If the air is at 100 percent relative humidity, sweat will not evaporate into the air. As a result, we feel much hotter than the actual temperature when the relative humidity is high. If the relative humidity is low, we can feel much cooler than the actual temperature because our sweat evaporates easily, cooling us off taken from How stuff Works Science.howstuffworks.com

6 WHERE ARE WE COMFORTABLE Summer accepted limits? 81 30%RH to 74 65%RH Humidity ratio range [X100]: Winter accepted limits? i 75 30%RH to 69 65%RH Humidity ratio range [X100]: Humidity Ratio: Humidity Ratio: Mass of water/mass of dry air Kg/Kg

7 WHERE ARE WE COMFORTABLE Summer accepted limits? 81 30%RH to 74 65%RH Humidity ratio range [X100]: Winter accepted limits? 75 30%RH to 69 65%RH Humidity ratio range [X100]: AS compared to Typical outside conditions per climates of interest Climate Typical loutside Condition i Humidity ratio Temp (F) RH kg/kg X100 Very Cold Marine Mixed and Humid Mixed and Dry Hot and Humid Hot and Dry Inside Comfortable Level

8 SENSIBLE VS LATENT SPLITS Q. How much of the total load is due to sensible heat losses/gains via conduction, convection, radiation VERSUS How much of the total load is due to latent Load? are we controlling to a humidity ratio (relative humidity)?? latent ventilation load where is the latent load generated from? CLIMATE SPECIFIC!

9 COST to remove MOISTURE It takes kwh / kg of water removed! this is a current figure looking at components available today WHAT is the COP of a DEHUMIDIFIER! How can we not add to the lt latent tload d passively? What can we CONTROL?

10 CONDENSATION ON MY WINDOWS! (inside) Q WHY? 1. The inside surface temperature of the glass is below the room dew point temperature! WHY AGAIN? 1. The inside RH is too HIGH 2. The glass R value is too LOW WHAT TO DO? Temperature RH DewPoint F % F

11 PRE TREATING incoming AIR GEOTHERMAL isn t just for heat pumps!! Geothermal simply stated is the use of heat stored in the ground! The center of the earth is HOT. It is continually cooling itself, inside to out Earth Air Tubes Ground Heat Exchangers

12 ERV vs. HRV In most applications it is better have moisture transfer 1. Hot humid outside condition: remove humidity from the incoming air = ERV 2. Cold outside dry inside: return as much humidity as possible to the inside = ERV 3. Cold outside excessively humid inside: exhaust some humidity, but not all = ERV If you always want to move all humidity from the outside to the inside, or from the inside to outside, or if the humidity inside and outside are always favorable = HRV

13 VENTILATION Exhaust only Supply only BALANCED Balanced: Mechanical: Ventilation: Heat Recovery: Energy Recovery: Airflow into and out of a defined volume in equal amounts Not passive? Usually with an electrical fan motor Controlled movement of airinto into and out of a building, generally using mechanical means, through deliberately placed holes in the Building Envelope John Bower The transfer of heat energy between air streams The transfer of heat and latent (moisture) heat energy between air streams

14 Types of Ventilators

15 PHPP and ventilation rates PHPP ill l l t i til ti fl d PHPP will calculate maximum ventilation flow, and average 24/7 operational flow Looking both at achieving 0.3 ACH per volume And looking at occupation driven requirements

16 Noise a nemesis with respect to air movement design to minimize noise

17 DEFINITIONS EER and SEER COP HSPF AFUE TON Energy Efficiency Ratio and Seasonal EER Window AC use EER. Central AC use SEER. BTU capacity divided by the wattage. In the case of SEER the ratio is defined by a particular season (climate). BTU/watt hour. Simplicity: Ave COP = * SEER Coefficient of performance. Unit less. Heat output divided by electrical lenergy input. BTU per Hr / BTU per Hr. Heating season performance factor. A measure of overall heating efficiency of a heat pump. Average seasonal COP. Ave COP = * HSPF Annual fuel utilization efficiency. The average thermal efficiency of the equipment for a year. 1 refrigeration ton = 12,000 BTU/hr. Heat (removed) required to melt 1 ton of ice (2000lbs.) in 24 hours.

18 TYPICAL AFUE VALUES Fuel Furnace/boiler AFUE Cast iron (pre 1970) 60% Heating oil Retention head burner 70 78% Mid efficiency 83 89% Central or baseboard 100% Electric heating Geothermal heat pump see COP Air source heat pump see HSPF Conventional 55 65% Natural gas Mid efficiency 78 84% Condensing 90 97% Conventional 55 65% Propane Mid efficiency 79 85% Condensing 88 95% Conventional 45 55% Firewood Advanced 55 65% State of the Art 75 90% Less tha an 1 COP P! Source: