Refrigeration system

Patent metadata

Field	Value
Publication number	US-10527334-B2
Application number	US-201214346279-A
Country	US
Kind code	B2
Filing date	Sep 26, 2012
Priority date	Sep 30, 2011
Publication date	Jan 7, 2020
Grant date	Jan 7, 2020

Abstract

A refrigeration system includes a heat source unit, a plurality of utilization units, a height-associated value detection unit and a pressure control unit. The heat source unit has a compressor and a heat source-side heat exchanger that functions as a radiator. Each utilization unit has a pressure reducer and a utilization-side heat exchanger that functions as an evaporator. The height-associated value detection unit detects a height-associated value of each utilization unit. The height associated value of each utilization unit corresponds to a height of the utilization unit. The height of each utilization unit is a vertical distance between the utilization unit and the heat source unit. The pressure control unit determines whether each of the utilization units is in operation or stopped and performs refrigerant pressure control based on the height-associated values of the utilization units that have been determined to be in operation.

First claim

What is claimed is:

1. A refrigeration system comprising:
a heat source unit having a compressor and a heat source-side heat exchanger that functions as a radiator;
a plurality of utilization units, each utilization unit having an expansion valve and a utilization-side heat exchanger that functions as an evaporator; and
a control unit including a microcomputer,
the microcomputer serving as:
a height-associated value detection unit configured
to detect height-associated values of each utilization unit, the height associated value of each utilization unit corresponding to a height of the utilization unit, the height of each utilization unit being a vertical distance between the utilization unit and the heat source unit, the plurality of utilization units being disposed at different vertical heights with respect to the heat source, and

an operation control unit configured
to determine whether each of the utilization units is an in-operation state or a stopped state, a plurality of utilization units being found to be in an in-operation state and at least one utilization unit being found to be in a stopped state,
to control a speed of the compressor during a cooling operation based on a height-associated value of the utilization unit disposed at a highest height among the plurality of the utilization units that have been determined to be in operation without using the height-associated value of the utilization unit that have been determined to be stopped,
to increase the speed of the compressor when the operation control unit determines that at least one of the plurality of utilization units disposed at a higher height becomes in operation, and
to decrease the speed of the compressor when the operation control unit determines that the utilization units disposed at a higher height are stopped and at least one of the plurality of utilization unit disposed at a lower height is in operation.

2. The refrigeration system according to claim 1 , wherein
the expansion valves have adjustable opening degrees, and
the height-associated value detection unit is configured to detect the height-associated values of the utilization units
by first having the refrigeration system perform a cooling operation using temporary height-associated values and
adjusting the temporary height-associated values based on changes in state of refrigerant with respect to adjustments to the opening degrees of the expansion valves.

3. The refrigeration system according to claim 2 , wherein
the height-associated value detection unit is further configured to
first have the refrigeration system perform a cooling operation using temporary height-associated values that are height-associated values of the utilization units in a case where the heights are zero,
repeatedly adjust the temporary height-associated values based on changes in the state of the refrigerant with respect to adjustments to the opening degrees of the expansion valves, and
when magnitudes of the changes in the state of the refrigerant with respect to the adjustments to the opening degrees of the expansion valves fall within a predetermined range, store the adjusted temporary height-associated values as the height-associated values of the utilization units.

4. The refrigeration system according to claim 3 , wherein
the height-associated value detection unit is further configured to adjust the temporary height-associated values based on changes in degrees of superheat of the refrigerant in outlets of the utilization-side heat exchangers with respect to adjustments to the opening degrees of the expansion valves.

5. The refrigeration system according to claim 1 , wherein
the expansion valves have adjustable opening degrees, and
the height-associated value detection unit is configured to detect the height-associated values of the utilization units by
first having the refrigeration system perform a cooling operation using temporary height-associated values that are height-associated values of the utilization units in a case where the heights are an upper limit,
determining amounts of refrigerant flowing through each of the utilization units, and
calculating pressures of the refrigerant when the refrigerant enters each of the utilization units from the opening degrees of the expansion valves of the utilization units.

6. The refrigeration system according to claim 1 , wherein
the height-associated value detection unit is configured to detect the height-associated value of each of the utilization units during a test operation performed at a time of installation of the heat source unit and the plurality of utilization units or during a cooling operation.

7. The refrigeration system according to claim 3 , wherein
the height-associated value detection unit is further configured to
periodically have the refrigeration system perform a cooling operation using temporary height-associated values that are smaller than the height-associated values of the utilization units that are stored and
redetect the height-associated values of the utilization units.

8. The refrigeration system according to claim 4 , wherein
the height-associated value detection unit is further configured to
periodically have the refrigeration system perform a cooling operation using temporary height-associated values that are smaller than the height-associated values of the utilization units that are stored and
redetect the height-associated values of the utilization units.

9. The refrigeration system according to claim 1 , wherein
the plurality of utilization units belong to any of a plurality of groups, and
the height-associated value detection unit is configured to detect the height-associated value of one of the utilization units in each of the groups and to apply the detected height-associated values to the other utilization units in the groups.

10. The refrigeration system according to claim 3 , wherein
the height-associated value detection unit is further configured to
periodically have the refrigeration system perform a cooling operation using temporary height-associated values that are smaller than the height-associated values of the utilization units that are stored and
redetect the height-associated values of the utilization units.

Assignees

• Daikin Ind Ltd

Inventors

• Nishimura Tadafumi
• Ishida Satoshi
• Matsui Nobuki

Classifications

• F24F11/89

  Arrangement or mounting of control or safety devices · CPC title

• F24F2221/50

  HVAC for high buildings, e.g. thermal or pressure differences · CPC title

• F24F3/065

  with a plurality of evaporators or condensers · CPC title

• F25B49/02 Primary

  for compression type machines, plants or systems · CPC title

• F24F2140/12

  Heat-exchange fluid pressure · CPC title