HEAT PUMPS
Heat pump heat multiplier. He takes the warm air and makes it hot air. This is done by compression of air and increasing its temperature. Heat pumps have received more attention, because the fuel embargo 1974. Energy saving became a more serious problem for all. If the device can be made to take heat from air and heat a home or commercial building, it is very useful to many people.
The heat pump can take the heat, refrigeration unit and use it to heat your home or room. Most take the heat out of the house and move it indoors (see Fig. 13.11). This device can be used for air conditioning the house in the summer and warm in winter, taking heat from outdoor air and moving it inside.
The soft-heating temperature days, heat pump handle heating needs. If the outside temperature reaches the equilibrium point homethat when the heat loss is equal to the heat pump heating capacitytwo stages indoor thermostat activates furnace (secondary source of heat, in most cases, the electric heating elements). Once the oven is on, thermal relay deenergises, the heat pump.
When the second stage (oven) need met the Plenum and cooled to a temperature below 90 and 100 degrees Fahrenheit, heat pump, switch turns the heat pump back and control the conditioned space until the second stage of the operation is necessary.
Fig. 13.12 shows a heat pump. Additional electric, thermal unit shown in Fig. 13.13 added in geographic locations where it is needed. This particular device can provide on 23 000 56 000 BTU / hour (Btuh) and to 112,700 Btuh with the addition of electric heat.
If the outdoor temperature drops below the level established for low-temperature compressor monitoring, control is deactivated heat pump fully, and furnace processes all heating needs. During the defrost cycle, the heat pump switches from heating to cooling. For ingress of cold air from the spread in the house, when the heating is necessary to control automatically switches to the furnace to compensate for the heat pump defrost cycle (see Fig. 13.14). When the supply air temperature rises above 110 to 120 degrees Fahrenheit, defrost control limit switches off the oven and keeps the air in the room becomes too warm.
If after defrost cycle, the air downstream of the coil rises above 115 degrees Fahrenheit, the last paragraph of heat pump relay, compressor stops until the heat exchanger cooled up to 90 to 100 degrees Fahrenheit, as it does during normal Cycling operation between the furnace and heat pumps...
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