Heat Pumps and Energy Savings
•GE Zoneline® Heat Pumps are designed to provide
The units employ a logic system monitoring both outdoor and indoor temperatures to determine the heat source, thus increasing energy savings by operating longer in the heat pump mode.
Heat pumps save energy and cost less to operate than units with electric resistance heaters as the only heat source. Just as the EER of an air conditioner is an indication of the efficiency of the unit, COP (Coefficient of Performance) is the indication of the efficiency of the heat pump. This relative efficiency of a heat pump compares the unit to electric resistance heat. If a unit has a COP of 3.0, it means the
unit will produce three times as much heat at rating conditions for the same electrical input wattage used for electric resistance heat.
The compressor is used in heat pump operation just as in air conditioning operation. In heat pump operation, the hot refrigerant gas is directed to the indoor coil rather than to the outdoor coil. Room air that circulates over the indoor coil gains heat from the coil rather than losing heat to the coil as during cooling operation.
As the outdoor temperature falls, the heat pump is able to extract less heat from the outdoor air to raise the temperature of the indoor air. For this reason, all packaged terminal heat pumps also have electric resistance heaters as backup to heat pump operation. At some point, the heat pump is unable to provide sufficient heat to adequately warm the room. Many Packaged Terminal Heat Pumps cease heat pump operation and change to more expensive resistance heat at some
the inability of the heat pump to maintain room temperature. This point, called the “switchover point,” is usually at an outdoor temperature where savings from heat pump operation may still be realized, if the unit is designed to maintain room comfort at the lower outdoor temperatures.
Balance Point
An important consideration of the selection of a heat pump unit is the “balance point” of the installation. Virtually every room is unique — with different insulation — different sizes and types of windows — different types of construction
—different directional exposures. All of these variables, as well as geographical location, must be considered in order to determine the balance point, the point at which the heat pump is unable to produce enough heat to compensate for the heat loss of the room or area being heated. For these reasons a consulting engineer should be engaged to calculate the heat loss and specify the heat pump unit required.
GE offers two series of Zoneline Heat Pump units — the 3900 Series with Standard Microprocessor controls and the 5800 Series with Highly Featured Microprocessor controls — and both series react to the indoor temperature as well as the outdoor temperature in determining the heat source to provide comfortable room conditions and energy savings. This determination of the heat source based on the indoor temperature helps provide a more comfortable room.
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