Heat source unit and refrigeration device
A heat source unit constitutes a refrigeration apparatus by being connected to a utilization-side unit. The heat source unit includes a low-stage compression element, a high-stage compression element, and a heat exchanger. The low-stage compression element has a discharge pipe provided with a pressure switchgear. The high-stage compression element compresses a refrigerant discharged from the low-stage compression element. When the low-stage compression element is paused in response to activation of the pressure switchgear, the high-stage compression element operates while the low-stage compression element is kept paused.
1. A heat source unit constituting a refrigeration apparatus by being connected to a utilization-side unit, the heat source unit comprising:
a low-stage compression element; a high-stage compression element; a heat exchanger; and a controller, wherein
the low-stage compression element has a discharge pipe provided with a pressure switchgear,
the high-stage compression element compresses a refrigerant discharged from the low-stage compression element,
the controller is configured to pause an operation of the low-stage compression element in response to activation of the pressure switchgear, and pause an operation of the high-stage compression element once and restart the operation of the high-stage compression element while the operation of the low-stage compression element is kept paused, thereby allowing refrigerant remaining in the discharge pipe of the low-stage compression element to be sucked by the high-stage compression element so as to reduce the pressure at the discharge pipe of the low-stage compressor element before restarting the low-stage compression element.
2. The heat source unit of claim 1 , further comprising:
a pressure equalization circuit configured to equalize a suction pressure and a discharge pressure of the high-stage compression element after the high-stage compression element is paused and before the high-stage compression element is restarted.
3. The heat source unit of claim 2 , further comprising:
a receiver provided between the heat exchanger and a liquid-side shutoff valve connected to the utilization-side unit, wherein
the pressure equalization circuit includes a venting pipe for the receiver.
4. The heat source unit of claim 3 , wherein
a valve provided in the venting pipe is kept open after the suction pressure and the discharge pressure of the high-stage compression element are equalized.
5. The heat source unit of claim 1 , wherein
the refrigerant is carbon dioxide.
6. The heat source unit of claim 2 , wherein
the refrigerant is carbon dioxide.
7. The heat source unit of claim 3 , wherein
the refrigerant is carbon dioxide.
8. The heat source unit of claim 4 , wherein
the refrigerant is carbon dioxide.
9. A refrigeration apparatus comprising the heat source unit of claim 1 .
10. A refrigeration apparatus comprising the heat source unit of claim 2 .
11. A refrigeration apparatus comprising the heat source unit of claim 3 .
12. A refrigeration apparatus comprising the heat source unit of claim 4 .
13. A refrigeration apparatus comprising the heat source unit of claim 5 .