US 4,157,649 A · Multiple compressor heat pump with coordinated defrost

Abstract

A method and apparatus for controlling a multiple compressor heat pump system such that when the system is in the heating mode of operation the compressors are cycled individually depending upon the ambient temperature level and are individually co-ordinately operated in a defrost mode. The electrical control means disclosed provides for a second compressor being energized when the outdoor heat exchanger of a first compressor is being defrosted and the first and second contact means located within the individual defrost circuits for the first and second outdoor heat exchangers such that when the first outdoor heat exchanger is being defrosted the second outdoor heat exchanger may not commence a defrost cycle and when the second compressor is being operated in a defrost cycle a first compressor may not commence a defrost cycle.

Claims15

Dependent claims

A heat pump system utilizing a refrigerant having first and second compressors operatively connected to first and second indoor heat exchangers providing heating and cooling to a conditiond region and first and second outdoor heat exchangers, first and second defrost means arranged to remove ice from the outdoor heat exchangers and thermostat means to actuate the compressors at the appropriate temperature levels, the improvement comprising:

a first defrost control circuit, which when energized during operation of the first compressor, activates the first defrost means to initiate a defrost cycle for the first outdoor heat exchanger operatively connected to the first compressor and which effects starting of the second compressor independent of the temperature within the conditioned region;
a second defrost control circuit which when energized activates the second defrost means to initiate a defrost cycle for the second outdoor heat exchanger operatively connected to the second compressor;
first contact means connected to the first defrost control circuit to prevent the initiation of a defrost cycle when the second defrost control circuit is in a defrost cycle;
and
second contact means connected to the second defrost control circuit to prevent the initiation of a defrost cycle when the first defrost circuit is in a defrost cycle.

2 more elements

A heat pump system having multiple compressors, first multiple heat exchangers at least one connected to each compressor to supply heating or cooling to an area to be conditioned, second multiple heat exchangers, and further comprising:

a first compressor control circuit having contact means to energize a first compressor and defrost means including a first defrost relay for activating a defrost cycle to defrost a first outdoor heat exchanger;
a second compressor control circuit having contact means to energize a second compressor and defrost means including a second defrost relay for activating a defrost cycle to defrost a second outdoor heat exchanger;
first contact means energized by the first defrost relay to energize the second compressor when the defrost cycle for the first outdoor heat exchanger is activated;
second contact means energized by the first defrost relay to de-energize the second defrost relay preventing a defrost cycle for the second outdoor heat exchanger when a defrost cycle for the first outdoor heat exchanger is activated;
and
third contact means energized by the second defrost relay to de-energize the first defrost relay preventing a defrost cycle of the first outdoor heat exchanger when a defrost cycle for the second outdoor heat exchanger is activated.

3 more elements

A method of operating a multiple compressor heat pump system having multiple compressors, multiple outdoor heat exchangers and multiple indoor heat exchangers operatively connected with the compressors, multiple defrost means for the appropriate outdoor heat exchangers, multiple fans associated with the appropriate heat exchangers and multiple reversing valves for changing the refrigerant flow direction within the heat pump operatively associated with each compressor and thermostat means for initiating compressor operation at the appropriate temperature levels, comprising the steps of:

selecting the appropriate mode of operation and number of compressors to be operated as a function of the desired system operation;
energizing a first compressor to transfer heat between a first indoor heat exchanger and a first outdoor heat exchanger under the appropriate loading conditions;
energizing a second compressor to transfer heat from a second outdoor heat exchanger to a second indoor heat exchanger when a first defrost means for the first outdoor heat exchanger is energized;
energizing both the first and second compressors to transfer heat between the first and second outdoor heat exchangers and the first and second indoor heat exchangers under the appropriate loading conditions;
de-energizing a second defrost means associated with the second compressor when the first defrost means associated with the first compressor is energized;
and
de-energizing the first defrost means associated with the first compressor when the second defrost means associated with the second compressor is energized.

4 more elements

Dependencies are inferred from the claim text.

Multiple compressor heat pump with coordinated defrost

Life of this patent

Multiple compressor heat pump with coordinated defrost

Life of this patent

Abstract

Claims15