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Home , Reversing valve

Heat Pumps An overview on operation and installation Weatherize Ohio 2018

Nick Milano [email protected] Background

• Air-source heat pumps have been used for many years in nearly all parts of the United States • Got a bad reputation for blowing cold air and causing high electric bills during the heating season • They had stopped being used in areas that experienced extended periods of below freezing temperatures • In recent years, air-source technology has advanced to the point that it is now offers a good space heating alternative in colder regions. Types of Heat Pumps

• Air to Air, uses outside air as the exchange medium • Ground Source, uses the constant temperature of the earth as the exchange medium • Water Source, uses water as the exchange medium (ponds wells) can be open or closed systems

• Absorption, uses another heat source, solar-heated water, geothermal heated water or natural gas rather than electricity as the exchange medium Air Source Heat Pumps • The most common type of Heat Pump • Heat Energy is present even in air that seems cold • During the heating season Heat Pumps extract heat from the outside air and transfer it inside • During the cooling season it reverses direction, removing heat from your home and transferring it to the outdoor air (Air Conditioner) • One advantage of a heat pump is that it moves heat instead of generating heat, giving you more energy efficiency • Can use approximately 50% less electricity compared to electric resistance heating ( and baseboard heaters) DOE • Mini-split Heat Pumps for homes without systems How They Work A heat pump's system consists of: • , makes a high temp, high pressure vapor • (TXV), controls flow (bypassed in heat mode) • The reversing valve changes the direction of the refrigerant flow for cooling and for defrosting the outdoor coil • Indoor and outdoor coils are made of copper tubing surrounded by aluminum fins to improve . • Liquid refrigerant in the outdoor coil extracts heat from the air evaporating it into a gas. • The indoor coil releases the heat from the refrigerant as it condenses back into a liquid. The Parts

Reversing valve Filter Drier

Thermal Expansion Valve (TXV) Compressor Indoor Coil Refrigeration Cycle As the outdoor coil extracts heat from the air, moisture in the air condenses on the outside coil. The moisture freezes and blocks the coil stopping the transfer of heat to the refrigerant. The unit has to go into ‘defrost’ to thaw the outdoor coil. The unit reverses the flow of refrigerant and operates in AC mode during defrost. A backup heat system is used to prevent the house from getting too cold during the defrost cycle Refrigeration Cycle The Delivery System

• The other major component of any heat pump is the ductwork. • Heat pumps can have problems with low airflow and leaky ducts. • There should be about 400 to 500 cfm airflow for each ton of the heat pump's capacity. • Efficiency and performance deteriorate if airflow is much less than 350 cfm per ton.

• Heat Pumps can be used to heat water that feeds into radiators. Efficiency

• SEER is Seasonal Energy Efficiency Rating, used to measure how much cooling a system puts out for each unit of energy it consumes • HSPF is Heating Seasonal Performance Factor, used to measure how much heating a system puts out for each unit of energy it consumes • The higher the number, the greater the efficiency

Outdoor Model Indoor Model Capacity Energy Use: Annual Energy Use Number Number EER SEER HSPF (kWh) 4SCU20LX124 BCE4M30S 23,000 14 20 10 1,850

4SCU20LX136 BCE4M36S 34,000 13.5 20 10 2,734

4SCU20LX148 BCE4M48S 48,000 12.5 19.5 9.6 3,989

4SCU20LX160 BCE4M60S 56,500 12.5 19 9.6 4,759 • SEER - ratio of the amount of cooling produced in BTU’s divided by the amount of electricity / watts used. Many older systems have a SEER rating of 10 or under. The lowest SEER available now is 13 • HSPF - ratio of the amount of heat produced in BTU’s divided by the amount of electricity / watts used. The lowest HSPF available now is 7.7 Best Practice Installation

Load Calculation • Do a Load Calculation to determine the required system size • 12,000 btu = 1 Ton • The required heat pump size is based on the cooling capacity. Heat pumps are offered in the same tonnage increments as AC units. • Once you have sizing requirements for the cooling side of your heat pump you then need to select the supplemental heating element. • Supplemental Heating Elements are in Kw and determined by your climates winter design temperature and required tonnage. • Manufacturers provide tables for this • 2.5 - 3.5 tons Heat Pump - Use a 15 Kw (0° F winter design temperature) Equipment • Outdoor unit • Properly sized, installed on snow legs / risers • Installed level on solid ground with proper clearances for optimum air flow • Outdoor electrical disconnect with properly sized wires in conduit • Correct size 220 volt breaker installed • Low voltage wires to outdoor unit and in good condition • Indoor Coil / • In a Heat Pump system the indoor coil and air handler are typically one unit • Properly sized air handler with coil matched to outdoor unit • Attached to a properly sized, sealed return and supply duct system • Properly sized supplemental heating element • Proper Heat Pump Thermostat • Line Set • Properly sized to the outdoor and indoor coils and for the installed length • Brazed with a nitrogen flow to eliminate contaminates • Properly insulated and supported • Liquid Line Filter/Dryer • Helps filter out damaging contaminants and moisture from system Set-up • Refrigeration System (Closed Loop) • Leak Check • Pull a Vacuum on the system to 29 in Hg • Release refrigerant from compressor Start-up • Indoor and Outdoor Units • Check and set Heating and Cooling Blower Speeds • Check and adjust refrigerant charge • Perform Temp rise and drop tests • Recheck and reset Heating and Cooling Blower Speeds • Recheck and adjust refrigerant charge Thank You

Nick Milano Ohio Partners for Affordable Energy [email protected]