Thermal system having hydronic system heat exchange
Process fluid from a hydronic system can be directed to an air-to-fluid heat exchanger in a heat exchange relationship with an outdoor heat exchanger of a thermal system connected to the hydronic system. The flow from the hydronic system to the air-to-fluid heat exchanger can be controlled using one or more valves. The process fluid at the air-to-fluid heat exchanger can defrost the outdoor heat exchanger, be used for free heating or cooling by being directed to a secondary load, or be used for balancing of cascade systems. A reversible fan can be provided at the outdoor heat exchanger and the air-to-fluid heat exchanger to facilitate these operations.
1 . A method, comprising:
exchanging heat between a working fluid of a thermal system and a process fluid circulated through a hydronic system in a first heat exchanger, wherein the process fluid circulated though the hydronic system includes supplying the process fluid from the first heat exchanger to a load and returning the process fluid from the load to the first heat exchanger; and
directing a portion of a flow of the process fluid from the hydronic system to an air-to-fluid heat exchanger, the air-to-fluid heat exchanger configured to exchange heat between the process fluid and an ambient environment at an outdoor heat exchanger of a working fluid circuit of the thermal system,
wherein the thermal system is a reversible thermal system that is configured to add or remove heat from the process fluid, and
the directing of the portion of the flow of the process fluid from the hydronic system to the air-to-fluid heat exchanger includes selectively controlling the portion of the flow of the process fluid from either a supply line of the process fluid supplying the process fluid to the load or a return line of the process fluid returning the process fluid to the first heat exchanger,
wherein the air-to-fluid heat exchanger is configured in a heat exchange relationship with the outdoor heat exchanger of the working fluid circuit such that during a defrosting operation, heat from the air-to-fluid heat exchanger melts frost buildup on the outdoor heat exchanger.
2 . The method of claim 1 , wherein the process fluid rejects heat to the outdoor heat exchanger.
3 . The method of claim 1 , wherein the directing the portion of the flow of process fluid from the hydronic system to the air-to-fluid heat exchanger is performed when the defrosting operation is determined, and further comprising directing airflow from the air-to-fluid heat exchanger to the outdoor heat exchanger to melt the frost buildup on the outdoor heat exchanger.
4 . The method of claim 1 , wherein the flow of process fluid, after leaving the air-to-fluid heat exchanger, is directed to the load, wherein the load is a cooling load of the hydronic system.
5 . The method of claim 1 , wherein the process fluid absorbs heat from the outdoor heat exchanger.
6 . The method of claim 1 , wherein the flow of process fluid, after leaving the air-to-fluid heat exchanger, is directed to the load, wherein the load is a heating load of the hydronic system.
7 . The method of claim 1 , wherein the process fluid is circulated between the hydronic system and a second hydronic system in a cascade system, and the process fluid rejects heat to the air-to-fluid heat exchanger such that the process fluid is provided to the second hydronic system at a target temperature.
8 . The method of claim 1 , wherein the thermal system is selected from the group consisting of a heat pump, a chiller, and a combined heating and cooling apparatus.
9 . A thermal system and hydronic system, comprising:
a thermal system configured to circulate a working fluid, the thermal system comprising:
a compressor;
an outdoor heat exchanger, configured to exchange heat between the working fluid and an ambient environment;
an expander; and
a first heat exchanger configured to exchange heat between the working fluid and a process fluid; and
a hydronic system configured to circulate the process fluid, the hydronic system comprising:
a supply line configured to convey the process fluid from the first heat exchanger to a load;
a return line configured to convey the process fluid from the load to the first heat exchanger;
an air-to-fluid heat exchanger configured to exchange heat between the process fluid and the ambient environment at the outdoor heat exchanger; and
one or more valves configured to regulate flow of the process fluid to the air-to-fluid heat exchanger,
wherein the thermal system and the hydronic system further include a controller configured to control the one or more valves to direct a portion of the flow of the process fluid from the hydronic system to the air-to-fluid heat exchanger by selectively controlling the portion of the flow of the process fluid from either the supply line or the return line,
wherein the air-to-fluid heat exchanger is configured in a heat exchange relationship with the outdoor heat exchanger such that during a defrosting operation, heat from the air-to-fluid heat exchanger melts frost buildup on the outdoor heat exchanger, and
the thermal system is a reversible thermal system that is configured to add or remove heat from the process fluid.
10 . The thermal system and hydronic system of claim 9 , further comprising:
a secondary load supply line configured to convey the process fluid from the air-to-fluid heat exchanger to a secondary load;
a secondary load return line configured to convey the process fluid from the secondary load to the air-to-fluid heat exchanger;
one or more valves configured to regulate flow of the process fluid from the air-to-fluid heat exchanger to the secondary load supply line; and
one or more valves configured to regulate flow of the process fluid from the secondary load return line to the air-to-fluid heat exchanger.
11 . The thermal system and hydronic system of claim 10 , wherein the secondary load is a cooling load.
12 . The thermal system and hydronic system of claim 10 , wherein the secondary load is a heating load.
13 . The thermal system and hydronic system of claim 9 , wherein the load is a second hydronic system, the second hydronic system in a cascade relationship with the hydronic system.
14 . The thermal system and hydronic system of claim 9 , wherein the controller is further configured to control at least one of the one or more valves to allow flow of the process fluid to the air-to-fluid heat exchanger and to direct airflow from the air-to-fluid heat exchanger to the outdoor heat exchanger to melt the frost buildup on the outdoor heat exchanger.
15 . The thermal system and hydronic system of claim 9 , further comprising a fan configured to direct airflow over the outdoor heat exchanger and the air-to-fluid heat exchanger.
16 . The thermal system and hydronic system of claim 15 , wherein the fan is reversible.
17 . The thermal system and hydronic system of claim 9 , wherein the thermal system further comprises a third heat exchanger, the third heat exchanger configured to exchange heat between the working fluid and a second process fluid of a second hydronic system, the second hydronic system configured to circulate the second process fluid to a second load.
18 . The thermal system and hydronic system of claim 17 , wherein the second hydronic system is configured to selectively provide the second process fluid to the air-to-fluid heat exchanger.
19 . The thermal system and hydronic system of claim 17 , further comprising at least one second air-to-fluid heat exchanger, wherein the second hydronic system is configured to selectively provide the second process fluid to the least one second air-to-fluid heat exchanger.
20 . The thermal system and hydronic system of claim 17 , wherein one of the load and the second load is a heating load, and the other of the load and the second load is a cooling load.