EP-4737818-A1 - APPARATUS AND METHOD FOR MODULATING HEATING OR COOLING CAPACITY OF A CLIMATE CONTROL SYSTEM WITH MULTIPLE REFRIGERANTS

EP4737818A1EP 4737818 A1EP4737818 A1EP 4737818A1EP-4737818-A1

Abstract

A climate control system includes: a working fluid including a blend of first and second refrigerants; an accumulator 144); a compressor (150) that receives the working fluid from the accumulator; a first heat exchanger 162) disposed downstream of the compressor; a liquid-to-suction heat exchanger (142) disposed downstream of the first heat exchanger and upstream of a receiver (148); a first expansion valve (146) disposed between the liquid-to-suction heat exchanger and the receiver; a second expansion valve (152) disposed between the receiver and a second heat exchanger, the second heat exchanger receiving the working fluid from the second expansion valve, at least partially vaporizing the working fluid, outputting the at least partially vaporized working fluid to the liquid-to-suction heat exchanger; and a control module (602) configured to selectively adjust opening of the first and second expansion valves based on (a) decreasing capacity and increasing working fluid concentration and (b) increasing capacity and decreasing working fluid concentration.

Inventors

WELCH, ANDREW M.
PLACE, KORY M.
ALDREDGE, Lonnie
MORGAN, STUART K.

Assignees

Copeland LP

Dates

Publication Date: 20260506
Application Date: 20251029

Claims (15)

A climate control system comprising: a working fluid comprising a blend of a first refrigerant and a second refrigerant; an accumulator; a compressor that receives the working fluid from the accumulator and compresses the working fluid; a first heat exchanger disposed downstream of the compressor; a liquid-to-suction heat exchanger disposed downstream of the first heat exchanger and upstream of a receiver; a first expansion valve disposed between the liquid-to-suction heat exchanger and the receiver; a second expansion valve disposed between the receiver and a second heat exchanger, wherein the second heat exchanger receives the working fluid from the second expansion valve and at least partially vaporizes the working fluid and outputs the at least partially vaporized working fluid to the liquid-to-suction heat exchanger; and a control module configured to selectively adjust opening of at least one of the first expansion valve and the second expansion valve based on (a) decreasing capacity and increasing working fluid concentration and (b) increasing capacity and decreasing working fluid concentration.
The climate control system of claim 1, further comprising a thermostat configured to measure a temperature of a space, wherein the control module is configured to, based on the temperature, selectively adjust the opening of at least one of the first expansion valve and the second expansion valve based on (a) decreasing capacity and increasing working fluid concentration and (b) increasing capacity and decreasing working fluid concentration.
The climate control system of claim 1 or claim 2, wherein the control module is configured to determine a difference between the temperature and a setpoint temperature, wherein the control module is configured to, based on the difference, selectively adjust the opening of at least one of the first expansion valve and the second expansion valve based on (a) decreasing capacity and increasing working fluid concentration and (b) increasing capacity and decreasing working fluid concentration.
The climate control system of any one of claims 1 to 3, wherein the control module is configured to determine a difference between a target concentration and a concentration of the second refrigerant determined based on operating parameters of the climate control system, wherein the control module is configured to, based on the difference, selectively adjust the opening of at least one of the first expansion valve and the second expansion valve based on (a) decreasing capacity and increasing working fluid concentration and (b) increasing capacity and decreasing working fluid concentration.
The climate control system of any one of claims 1 to 4, wherein the control module is configured to close the second expansion valve and modulate the first expansion valve based on decreasing capacity by increasing working fluid concentration of the second refrigerant circulating the system; and/or wherein the control module is configured to open the second expansion valve and modulate the first expansion valve based on increasing capacity by decreasing working fluid concentration of the second refrigerant circulating the system.
The climate control system of any one of claims 1 to 5, wherein the control module is further configured to maintain capacity by modulating the openings of the first and second expansion valves based on maintaining the working fluid concentration.
The climate control system of any one of claims 1 to 6, wherein the control module is configured to close the second expansion valve to at least one of (a) increase the subcooling and (b) decrease the vapor quality leaving the condenser and modulate opening of the first expansion valve.
The climate control system of any one of claims 1 to 7, wherein the control module is configured to close the second expansion valve and modulate opening of the first expansion valve based on a predetermined target concentration of the working fluid; optionally wherein the control module is configured to modulate the first expansion valve by adjusting characteristic of a signal applied to the first expansion valve.
A climate control method comprising: by a compressor, receiving a working fluid from an accumulator and compressing the working fluid, wherein the working fluid comprises a blend of a first refrigerant and a second refrigerant; by a first heat exchanger, receiving the working fluid from the compressor; by a liquid-to-suction heat exchanger, receiving the working fluid from the first heat exchanger and outputting the working fluid toward a receiver; by a first expansion valve, receiving the working fluid from the liquid-to-suction heat exchanger and outputting the working fluid to the receiver; by a second expansion valve, receiving the working fluid from the receiver and outputting the working fluid toward a second heat exchanger, wherein the second heat exchanger at least partially vaporizes the working fluid and outputs the at least partially vaporized working fluid to the liquid-to-suction heat exchanger; and selectively adjusting opening of at least one of the first expansion valve and the second expansion valve based on (a) decreasing capacity and increasing working fluid concentration and (b) increasing capacity and decreasing working fluid concentration.
The climate control method of claim 9, further comprising by a thermostat measuring a temperature of a space, and based on the temperature, selectively adjust the opening of at least one of the first expansion valve and the second expansion valve based on (a) decreasing capacity and increasing working fluid concentration and (b) increasing capacity and decreasing working fluid concentration; said climate control method optionally further comprising: determining a difference between the temperature and a setpoint temperature; and based on the difference, selectively adjust the opening of at least one of the first expansion valve and the second expansion valve based on (a) decreasing capacity and increasing working fluid concentration and (b) increasing capacity and decreasing working fluid concentration.
The climate control method of claim 9 or claim 10, further comprising: determining a difference between a target concentration and a concentration of the second refrigerant determined based on operating parameters of the climate control system; and based on the difference, selectively adjust the opening of at least one of the first expansion valve and the second expansion valve based on (a) decreasing capacity and increasing working fluid concentration and (b) increasing capacity and decreasing working fluid concentration.
The climate control method of any one of claims 9 to 11, further comprising closing the second expansion valve and modulating the first expansion valve based on decreasing capacity by increasing working fluid concentration of the second refrigerant circulating the system; and/or opening the second expansion valve and modulating the first expansion valve based on increasing capacity by decreasing working fluid concentration of the second refrigerant circulating the system.
The climate control method of any one of claims 9 to 12, further comprising maintaining capacity by modulating the openings of the first and second expansion valves based on maintaining the working fluid concentration.
The climate control method of any one of claims 9 to 13, further comprising closing the second expansion valve to at least one of (a) increase the subcooling and (b) decrease the vapor quality leaving the condenser and modulate opening of the first expansion valve.
The climate control method of any one of claims 9 to 14, further comprising closing the second expansion valve and modulating opening of the first expansion valve based on a predetermined target concentration of the working fluid; said climate control method optionally further comprising modulating the first expansion valve by adjusting characteristic of a signal applied to the first expansion valve.

Description

FIELD The field of the present disclosure relates to climate control systems for use with working fluids having refrigerant blends exhibiting high glide and methods for operating the same, and more specifically to climate control systems having a liquid-to-suction heat exchanger, a heat exchanger, an accumulator, and a receiver for controlling refrigerant concentrations. BACKGROUND The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. A thermodynamic climate control system such as, a heat-pump system, a refrigeration system, or an air conditioning system may include a fluid circuit having a first heat exchanger (e.g., a condenser that facilitates a phase change of refrigerant from gas/vapor to a liquid) that is typically located outdoors, a second heat exchanger (e.g., an evaporator that facilitates a phase change of refrigerant from liquid to gas/vapor) that is typically located indoors or within the environment to be cooled, a receiver that operates to store liquid refrigerant between the first and second heat exchangers (e.g., condenser and evaporator), an accumulator that operates to store liquid phase refrigerant upstream of the second heat exchangers (e.g., evaporator), a liquid pump disposed between the first and second heat exchangers, expansion devices disposed between the first heat exchanger (e.g., condenser) and the receiver and between the receiver and the second heat exchanger (e.g., evaporator), and a compressor disposed between the first and second heat exchangers that operates to pressurize gas/vapor phase refrigerant. These types of systems can be fixed, such as at a building or residence, or can be mobile, such as in, or as part of a vehicle. For example, vehicles include land based vehicles (e.g., trucks, cars, trains, etc.), water based vehicles (e.g., boats, sea containers), air-based vehicles (e.g., airplanes), and vehicles that operate over a combination of more than one of land, water, and air. There is growing pressure to adopt refrigerants with lower global warming potential (GWP) due to environmental concerns. Traditional synthetic refrigerants are being reconsidered in favor of natural refrigerants, which can offer a more eco-friendly alternative. The shift towards these natural refrigerants introduces new challenges which include device applicability, environmental acceptability and safety. While natural refrigerants present a promising solution to reduce environmental impact, their adoption requires careful management of these associated challenges. Synthetic refrigerants may be replaced by natural refrigerants in some climate control applications. Further, in order to use lower global warming potential refrigerants, the flammability of the refrigerants may increase. Several refrigerants have been developed that are considered low global warming potential options, and they have an ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) classification as A2 (relatively lower flammability than A3 refrigerants), A2L (mildly flammable/lower flammable than A2 and A3 refrigerants and lower toxicity), or A1 (no flame propagation/lower toxicity levels). Examples of an A2 refrigerant include 1,1-difluorethane (R-152A - as used herein, the refrigerants may be interchangeably described by the conventional nomenclature of "R" for refrigerants or their specific chemical class code, like HFC-152A) with a global warming potential of about 124, while examples of A2L refrigerants include difluoromethane (CH2F2 or R-32 - as used herein, the refrigerants may be interchangeably described by the conventional nomenclature of "R" for refrigerants or their specific chemical class code, like HFC-32) with a global warming potential of about 677, and hydrofluorolefins (HFOs), like 2,3,3,3,-tetrafluoroprop-1-ene (HFO-1234yf or R-1234yf), trans-1,3,3,3,-tetrafluoroprop-1-ene (HFO-1234ze or R-1234ze). A1 refrigerants include carbon dioxide (CO2 or R-744), which has a desirably low global warming potential of 1, 1-chloro-3,3,3-trifluoropropene (cis- and trans-HFO-1233zd(Z) or R-1233zd (Z) and HCFO-1233zd(E) or R-1233zd (E)), chlorodifluoromethane (R-22 or CHCIF2), R-410A that is a near-azeotropic mixture of difluoromethane (HFC-32) and pentafluoroethane (HFC-125), and other hydrocarbon refrigerants, such as hexane, heptane, octane, nonane, and decane. It would be desirable to employ climate control systems that can successfully employ such environmentally friendly refrigerants with low global warming potential. SUMMARY In a feature, a climate control system includes: a working fluid comprising a blend of a first refrigerant and a se