Patent Application
20230417434
Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Heat pumps are useful for many purposes. A prominent application for a heat pump is as a component for a Heating, Ventilation, and Air Conditioning (HVAC) system used to control ambient temperature within an environment. One example of such an environment is a residential or industrial building space.
Heat pumps are complex mechanisms. They can include refrigerant circulation networks comprising conduits, heat exchangers (e.g., coils), valves, and pumps, as well as other air circulation networks comprising other conduits, heat exchangers, valves, and pumps.
On occasion, a heat pump may experience a failure. Such failed operation of a heat pump can imperil the well being of individuals and/or devices that are relying upon HVAC systems in order to maintain a safe ambient temperature within a space.
An electrical interface selectively places a heat pump and a backup temperature control device in alternative electrical communication with a single power feed, thereby simplifying installation and reducing cost. In particular embodiments, a compressor of the heat pump may be in selective electrical communication with the power feed via a normally closed relay. Removal of a control voltage results in opening of the normally open relay, and closing of a normally closed relay to place the backup temperature control device in selective electrical communication with the power feed. For a ground source heat pump, a ground loop pump may also be in selective electrical communication with the power feed (e.g., via a normally closed relay).
Described herein are methods and apparatuses implementing an electrical interface with a heat pump. In the following description, for purposes of explanation, numerous examples and specific details are set forth in order to provide a thorough understanding of embodiments according to the present invention. It will be evident, however, to one skilled in the art that embodiments as defined by the claims may include some or all of the features in these examples alone or in combination with other features described below, and may further include modifications and equivalents of the features and concepts described herein.
A compressor (COMP) 102 functions to move a working fluid through a circuit 104. The compressor is electrically connected to a power feed 106 via an electrical interface 108 in order to operate.
A working fluid may comprise a refrigerant. A working fluid may experience a phase change as it circulates through the circuit.
A primary side heat exchanger 110 functions to exchange heat with the controlled temperature space 112. The controlled temperature space may be the inside of a building, for example. A fan 113 may operate to assist in the circulation of air within the space.
A secondary side heat exchanger 114 operates to source/sink heat into a thermal reservoir 116 located outside of the temperature controlled space.
The specific (ground) heat pump system of
Some heat pump systems may rely upon the temperature of outside air to serve as a thermal reservoir. Particular heat pump systems could even rely upon a source of geothermal energy, in order to serve as a thermal reservoir.
During the heating mode of operation shown in
A metering valve 118 regulates the flow of refrigerant through the circuit. A reversing valve 120 changes a direction of flow of the refrigerant, allowing the circuit to selectively extract or add heat to the temperature controlled space.
To mitigate risks associated with loss of temperature control in the event of a system failure, as shown in
To operate this backup temperature control device, electrical power is required. Thus, embodiments provide the electrical interface which avoids the need for a second power feed for the backup device. This reduces cost and complexity of the heat pump installation.
In particular, the compressor and the water pump are in communication with a first output 132 of the electrical interface. Under normal operating conditions, power from the power feed is routed to the first output.
The electrical interface also includes a control input 133 and a second output 134. Upon removal of the control input, the electrical interface communicates power from the power feed to the backup temperature control device, rather than to the compressor.
In particular, specific embodiments provide a way of connecting power to multiple elements of the system, by using a set of relays. These relays reliably provide electrical power to the compressor, while offering a robust and mechanical structure of isolating the compressor and providing power to the backup temperature control device in the event of failure.
In the embodiment of
One example of a candidate relay suitable for use is the Relay Module NO/NC CO Contact available from Peters Indu-Produkt of Germany. This is an example of a singular unit containing NO and NC contacts.
Embodiments could also be implemented in two (2) relays, one NO and one NC powered by the voltage signal. An example is the DPST 1 NO 1 NC 8 Amp Power Relay Module available from CZH-LABS of Shenzhen, China.
The contactors are switched using application of a control voltage to close Normally Open relay 310 and thereby provide power to the compressor (COMP). Normally Closed relay 312 is opened by application of a control voltage 302 and thereby isolates the backup heater from the power feed.
Utilizing an embodiment of an electrical interface as shown in
At 404, the heat pump compressor and pump are selectively electrically isolated from the power feed in response to removal of a control voltage. At 406 a backup temperature control device is selectively placed in electrical communication with the power feed in response to the control voltage removal.
The above description illustrates various embodiments of the present invention along with examples of how aspects of the present invention may be implemented. Other embodiments are possible.
For example, while the above description discloses the backup temperature control device as being a heater, this is not required. Alternative embodiments could feature a backup temperature control device that is a cooler, or a combination heater/cooler.
Moreover, while the above description discloses that removal of a control voltage results in opening of a normally open relay, and closing of a normally closed relay, this is not required. According to alternative embodiments, receipt of a control voltage may result in opening of a normally closed relay, and closing of a normally open relay.
The above examples and embodiments should not be deemed to be the only embodiments, and are presented to illustrate the flexibility and advantages of the present invention as defined by the following claims. Based on the above disclosure and the following claims, other arrangements, embodiments, implementations and equivalents will be evident to those skilled in the art and may be employed without departing from the spirit and scope of the invention as defined by the claims.
