Heat pump diagram thermodynamics. Their analysis uncovers the working .
Heat pump diagram thermodynamics. The diagram below shows this relationship for R410a.
Heat pump diagram thermodynamics The heating capacity of the system is improved because more refrigerant in the EVIHP system enters the condenser through the Air source heat pumps extract heat from the outdoor air, while ground source heat pumps extract heat from the ground. Heat pumps can carry heat from low temperature. If the purpose of the thermal pump is to remove heat from somewhere cold, we call it a refrigerator. In this section we will concentrate on its heating mode. In general, the term heat pump is used to describe the cycle as heat energy is removed from the low-temperature space and Nov 12, 2018 · As an example we know that water will carry thermal energy away as steam when it boils and we know it boils at 100*C (212*F) well if we look at some common heat pump refrigerants, R134a has a boiling point of -26. , outdoor air in the winter) and delivers (more) heat to a heat source (e. A refrigerator and a heat pump are both devices that operate based on the principles of thermodynamics. Heat pumps are also often used in a reverse setting to cool rooms in the summer. The term heat pump is usually reserved for a device that can heat a house in winter by using an electric motor that does work W to take heat Q cold from the outside at low temperature and delivers heat Q hot to the warmer inside of the house. For an air conditioner, heat is transferred outdoors from inside a home. 3. This study aims to systematically introduce the thermodynamic description of elastocaloric cooling and heat pump cycles by derivation from the classical first law and the second law of thermodynamics. Therefore, you can tell by the sign Apr 10, 2024 · A refrigerator (or heat pump) absorbs heat \(Q_c\) from the cold reservoir at Kelvin temperature \(T_c\) and discards heat \(Q_h\) to the hot reservoir at Kelvin temperature \(T_h\) while work W is done on the engine’s working substance, as shown by the arrow pointing toward the system in the figure. Apr 5, 2020 · I'm no expert on heat pumps, but I've read that the typical range of COP for actual air source heat pumps is 3-4. Heat pump heat exchangers (E, K and soil borehole) were presumed to have constant effectiveness Heat Pump Diagram Thermodynamics Heat Pumps Kazimierz Brodowicz,Tomasz Dyakowski,M L Wyszynski,Wyszynski,2013-10-22 Heat pumps and related technology are in widespread use in industrial processes and installations This book presents a unified comprehensive and systematic treatment of the A heat pump cycle makes a hot body (or space) hotter. We can only define a thermal efficiency for power cycles. 3). In the heating mode, heat transfer Q c Q c size 12{Q rSub { size 8{c} } } {} occurs to the working fluid in the evaporator (3) from the colder outdoor air, turning it into a gas. 1. 2) Heat engines do net work, heat pump/refrigerators take in net work. Taking the maximum of the range (4) and using it in our example, the min work required becomes 1000/4 = 250 J. Aug 3, 2024 · Smith and Kemler's 1940s water-well heat pump is not the world's first geothermal pump, but it's the earliest one for which I can find a decent diagram. , in detail here at Embibe. (a) Schematic diagram showing heat transfer from a cold reservoir to a warm reservoir with a heat pump. But whether a heat pump is right for you depends on many variables. 1, as a refrigerator. A geothermal heat pump, also called a ground-source heat pump, is used to carry the heat exchange fluid (water with a little antifreeze) from the soil or from groundwater. Operation Heating Cycle Dec 15, 2021 · Notes on Thermodynamics, Fluid Mechanics, and Gas Dynamics 3. As the device operates in cycles, the heat flows and work should be understood as referring to one cycle. 2 Heat pumps, air conditioners, and refrigerators are heat engines operated backward. A heat pump is a device that consumes Temperature–entropy diagram of the vapor-compression cycle An internal view of the outdoor unit of an Ecodan air source Feb 2, 2011 · Heat pumps are devices that operate in a cycle similar to the vapor-compression refrigerator cycle illustrated in Figure 1. Process heating: In industries, the heat pump is used to heat the process fluid before the reactions. If the net power or work into the cycle is positive, then we call the device a refrigeration or heat pump cycle (sometimes this is called a reversed power cycle): \[\dot{W}_{\text {net, in }} \text { or }\left. Figure 19. 5 applications of thermodynamics: heat pumps and refrigerators. A heat pump schematic diagram is a visual representation of the heat pump system, highlighting its key components and their connections. A refrigerator (or heat pump) absorbs heat Q c Q c from the cold reservoir at Kelvin temperature T c T c and discards heat Q h Q h to the hot reservoir at Kelvin temperature T h, T h, while work W is done on the engine’s working substance, as shown by the arrow pointing toward the system in the figure. path that the fluid must take between inlet and outlet) and how the work is done. 18. Applying thermodynamic principles to the operation of a heat pump shows that to move thermal energy from the cold environment outside the house to the warm environment inside the house requires an input of work. The directions of , , and are opposite what they would be in a heat engine. ) Figure 2. Energy is conserved Heat Pump Diagram. The fluid used to heat the pump cycle is called a refrigerant. In general, the term heat pump is used to describe the cycle as heat energy is removed from the low-temperature space and Jan 25, 2023 · Elastocaloric cooling is an emerging solid-state cooling technology and has experienced fast development over the last decade. 34*F) and R410A has a boiling point of -48. Power Up for Progress! Celebrate Energy Conservation Day with discounts on all plans. Heat pump cycles Thermodynamic heat pump cycles are the models for heat pumps and refrigerators. Heat pumps are an eco-friendly solution. Some heat pumps can even provide hot water for domestic use. As it turns out, a heat pump can both heat and cool a building — but how does a heat pump work Furthermore, the initial cost of a heat pump is greater than that of many furnaces, so that a heat pump must last longer for its cost to be recovered. Each refrigerant has a specific Pressure/Enthalpy diagram that shows how the substance performs under different pressure and enthalpy conditions. Heat pump and refrigeration cycles can be classified as vapor compression, vapor absorption, gas cycle, or Stirling cycle types. GSHPs are one of the most energy-efficient technologies for heating, ventilation, air conditioning T-Q diagram is a derivative of temperature-heat flow (T-q) diagram for heat exchanger in the theory of entransy (Chen et al. Diagram of water to water heat pump. 5 WORK DONE BY THE PUMP The role of a pump (a) Schematic diagram showing heat transfer from a cold reservoir to a warm reservoir with a heat pump. (Actually, a heat pump can be used both to heat and cool a space. Heat pumps, air conditioners, and refrigerators are heat engines operated backward. Dec 21, 2023 · Heat physics pump thermodynamics compressor simple pumps condenser valve transfer evaporator expansion components refrigerators diagram air law work working temperature Heat pump piping schematic10 electrical riser diagram template Understanding air to water heat pump systems : part 1Riser dwg cadbull. This model is based on the thermodynamic principals and heat transfer For home heating, a heat pump extracts heat from outside air, heats the warm air up even more, and transfers it indoors. A heat pump can be thought of as heat engine which is operating in reverse. This diagram provides an invaluable resource for homeowners, helping them understand how their heat pump operates and potentially diagnose any issues. Thermodynamics Heat cycles 1 / 8 Heat Pump RECORD AND ANALYSE THE PRESSURE-ENTHALPY DIAGRAM FOR A COMPRESSION HEAT PUMP Demonstrate how an electric compression heat pump works Quantitatively investigate of the related cyclical process Record and analyse the pressure-enthalpy diagram for a compression heat pump UE2060300 03/18 UD Heat carriers were assumed to have constant heat capacities,C 6 K = 500 W/K = const. Enthalpy is a measure of the amount of heat contained in a substance. Here, I've colored and numbered to show how it works as a heat pump. This heat pump can be used to cool buildings by transferring heat from the hot areas into the soil via the ground loop or piping placed within the ground. The purpose of this engine is to remove heat from the cold reservoir, which is the space inside the refrigerator for an actual household refrigerator or the space inside a building for an air-conditioning unit. The Ts diagram typically consists of a closed loop that represents the thermodynamic cycle of the heat pump. The points represent the different components of the heat pump. There will be a quantity of heat rejected at the higher temperature and a quantity of heat absorbed at the lower temperature. Applying the first law of thermodynamics to the heat pump cycle, we can derive (Actually, a heat pump can be used both to heat and cool a space. As we will show below, it is the most efficient heat pump operating between two given temperatures. interested in the heat energy removed from a low-temperature space, the device is called a refrigerator. g. REFRIGERATOR (OR HEAT PUMP) IS A DEVICE TO TRANSFER HEAT FROM A LOW TEMPERATURE MEDIUM TO A HIGH TEMPERATURE MEDIUM. In the heating mode, heat transfer Q c Q c occurs to the working fluid in the evaporator (3) from the colder outdoor air, turning it into a gas. When you think about cooling a hot building, you probably don't think of heat pumps. In conclusion, a residential heat pump is a versatile heating and cooling system that transfers heat energy from one location to another using electricity. . Like most heat pumps, it can run as either a heater or a cooler. 3 °C (-15. Figure 112. The sizing of the system should be based on the specific heating and cooling needs of the building or application. 1). Heat pump cycle heating process involved figure parts energy Heat pump motor wiring diagram Sale > heat pumps air conditioning > in stock Heat Pump Diagram Thermodynamics Heat Pumps Kazimierz Brodowicz,Tomasz Dyakowski,M L Wyszynski,Wyszynski,2013-10-22 Heat pumps and related technology are in widespread use in industrial processes and installations This book presents a unified comprehensive and systematic treatment of the Oct 12, 2024 · T-s diagram for heat pump cycle. no Abstract Heat pumps are an attractive heating system in residential buildings. Figure 15. Vapor Compression Refrigeration and Heat Pump Cycles The objective of a vapor compression refrigeration cycle is to remove energy from a cold reservoir and move Nov 10, 2023 · Air source heat pumps might be an alternative to typical HVAC units. Characteristics of Refrigerators/Heat Pumps a) Refrigerator/heat pump receives heat from a low temperature medium (ice box of refrigerator, outdoor air, etc. This pressure/heat energy chart lets us sketch out the desired behavior for our heat pump. A heat pump uses the same vapour compression refrigeration cycle, see Figure 6. Download scientific diagram | Heat pump cycle with refrigerant R410A in terms of an enthalpy and pressure diagram from publication: Influence of Parameters on the Estimation of Coefficient of Heat pump work pumps air source does energy water system systems typical get cycle evaporator refrigerant types coil gif mechanical What is second law of thermodynamics? [8+ best examples & equation] Hyperphysics heat pump energy thermo thermodynamics engine flow Mechanical engineering thermodynamics Unlike the situation with steam power plants it is common practice to begin the design and analysis of refrigeration and heat pump systems by first plotting the cycle on the P-h diagram. Their analysis uncovers the working A heat pump is an electric device used to pull heat out of air, ground or water and transfers it to the building. Enthalpy flows across the cells through four interfaces as a result of mass flow being, respectively, compression space/heater, heater 3. The result is a cycle that operates in the counterclockwise direction on a T-s diagram, which is called the reversed Carnot cycle. Appropriate thermodynamics of refrigeration cycles are essential for efficient operation of a heat pump. Furthermore, the initial cost of a heat pump is greater than that of many furnaces, so that a heat pump must last longer for its cost to be recovered. In this diagram a heat pump with a condensation temperature of 80 °C and an evaporation temperature of 40 °C is taken as an example. Let us now see what we can learn about our heat pump from some basic physics. 2 Diagram of an air-to-water heat pump. Nimur/Shutterstock. What the First Law of Thermodynamics Tells Us About a Heat Pump Figure 15. Which device maintains a body at a temperature lower than the temperature of the surroundings? a) PMM1 b) PMM2 c) refrigerator d) heat pump View Answer Generally, the operation process of the heat pump system is 1-2-3-4-1. Heat Engines Lecture 7 11 21 UCSD Heat Pumps and Refrigerators: Thermodynamics T h directions of any heat and work interactions. 2. However, by exploring the thermodynamic diagram associated with a heat pump, we can gain a deeper understanding of how it functions and how its performance can be optimized. A household refrigerator removes heat This set of Thermodynamics Multiple Choice Questions & Answers (MCQs) focuses on “Refrigerator and Heat Pump”. Comparison of various heat pumps. Heat pumps thermodynamics refrigerators physics applications pump diagram cycle carnot air system figure graph transfer work chapter indicated shows circle Chair interpretive helplessness heat pumps vs gas boilers vice duringHeating underfloor systems layout floor radiant water hydronic so solutions click We represent a heat engine and a heat pump cycle in a minimalist abstract format as in the following diagrams. 3 How does an air-to-water heat pump work? 3. HTR QIN LTR QOUT WIN Refrig. Dec 20, 2024 · The heat pump is configured by five components serially connected, and the working gas in the heater/hot heat exchanger and cooler/cold heat exchanger is kept under isothermal conditions; see Fig. 4. Satyanarayanan Seshadri, Chief Technology Officer at Aspiration Energy, and the Director of Energy and Emissions Lab at IIT Madras. When we are interested in the heat energy supplied to the high-temperature space, the device is called a heat pump. Heat pumps are most likely to be economically superior where winter temperatures are mild, electricity is relatively cheap, and other fuels are relatively expensive. 2 Heat pump. T-s diagram of the Carnot heat pump cycle T s p 1 p 2 1 T 1 = T c 3 2 T 3 = T h 4 Lecture 36 – Heat pumps - Purdue ME 200, Thermodynamics I Author: Kevin J In buildings a heat pump may be used for heating or cooling (more commonly known as air conditioning). The log p-h diagram shows a cycle for a mechanical heat pump. 5 WORK DONE BY THE PUMP The role of a pump The heat loss (Q E) and the work done on the system (W), which are not thermodynamic properties, are on the left-hand side of the equation. Oct 6, 2024 · Heat Pump Process Diagram Heat Pump!!! – Thermodynamics Te 06 Oct 2024. The following schematic shows a basic refrigeration or heat pump system with typical property values. It absorbs heat from a heat sink (e. (b) diagram for a Carnot cycle similar to that in Figure 3 but reversed, following path ADCBA. 1 Diagram of an air-to-air heat pump. Heat pump cycles and refrigeration cycles can be classified as vapor compression, vapor absorption, gas cycle, or Stirling cycle types. Simultaneous or separate needs for heating and cooling energy can be satisfied with the use of a heat pump. Heat pumps compress cold ambient air and, in so doing, heat it to room temperature without violation of conservation principles. 29 A simple heat pump has four basic components: (1) condenser, (2) expansion valve, (3) evaporator, and (4) compressor. W_{\text {net, in }}\right|_{\text {cycle }}>0 \quad \rightarrow \quad \begin{array}{c} \text { Refrigeration or } \\ \text{ heat pump An Overview of a Heat Pump Schematic Diagram. A refrigerator or heat pump that operates on the reversed Carnot cycle is called a Carnot refrigerator or a Carnot heat pump Jul 4, 2024 · In essence, a thermal pump is a heat engine operating in reverse. In both cases there are two temperature reservoirs T H and T L , with T H > T L . 28 A simple heat pump has four basic components: (1) condenser, (2) expansion valve, (3) evaporator, and (4) compressor. Example \(\PageIndex{1}\): The Best COP hp of a Heat Pump for Home Use. Thermodynamics is an intrinsic part of our daily lives. Such a solution is undoubtedly very energy efficient and economically successful. The Heat Pump Cycle. Various flow sheets and diagrams for heat pumps (using inverse thermodynamic cycles) were suggested in literature to recover the energy from secondary (or residual) sources, all of them presuming (a) Schematic diagram showing heat transfer from a cold reservoir to a warm reservoir with a heat pump. Air source heat pumps. 6. Diagram of a geothermal heat pump. Heat pump theory is based on the second law of thermodynamics, which says that heat passes from hi. In the case of a heat engine heat Q H is extracted from the high temperature source T H , part of that heat is converted to work W done on the Dec 6, 2022 · 2. The directions of W size 12 {W} {}, Qh size 12 {Q rSub { size 8 {h} } } {}, and Qc size 12 {Q rSub { size 8 {c} } } {} are opposite what they would be in a heat engine. For a heat pump, the focus is on dumping heat to a specific area. Oct 6, 2024 · Heat physics pump thermodynamics compressor simple pumps condenser transfer valve evaporator expansion components refrigerators diagram air law work working applicationsApplications of thermodynamics: heat pumps and refrigerators Thermodynamics team b – uw-green bay15. Heat pumps are an essential component of many heating and cooling systems, but understanding their thermodynamics can be a challenging task. Sep 5, 2023 · Yu and Ouderji compare the thermodynamic performance of the flexible heat pump cycle with other performance enhancing cycles using a unified approach. Aug 30, 2024 · For those deep into engineering thermodynamics, the H-S diagram can also be used to derive the efficiency of thermodynamic cycles. , indoor air) by consuming work. Water heating: Water in industries and households is heated using heat recovered from other reactions using the heat pump. Some heat pumps are designed to heat water instead of air. 4. Second Law of Thermodynamics for Heat Pump. 6, this heat could be used for space heating. Heat pumps and air conditioners operate in a very similar way; the difference is that the heat pump cycle can be reversed to either heat or cool a controlled space. b) Heat is rejected to a high temperature Apr 25, 2021 · The detailed exergy analysis and comparison of annually averaged exergy efficiencies of different heat sources in space heating operation mood, shows the best results in the case of a system based on a water–water heat pump, assisted with solar thermal collectors and seasonal heat storage . The difference between the two is that heat pumps are intended to keep a place warm while refrigerators are designed to cool it. The Laws of Thermodynamics 1. Jul 29, 2020 · This process can be easily visualized on a Pressure/Enthalpy diagram. The heat loss (Q E) and the work done on the system (W), which are not thermodynamic properties, are on the left-hand side of the equation. In the case of a refrigerator, heat is moved out of the inside of the fridge into the surrounding room. In fact, you likely think of using an air conditioner. It is essentially an air conditioner and a heating unit all in one. When used for heating the evaporator is located somewhere in the external environment. e. Suppose we want to run our cold heat exchanger (outdoors) at 20°F and our hot heat exchanger (indoors) at 100°F. , 2012) and temperature-enthalpy (T-H) diagram in pinch analysis (Kemp One important factor for optimizing the performance of a water to water heat pump is proper sizing. The diagram below shows this relationship for R410a. A household refrigerator removes heat from Apr 1, 2024 · Heat pumps physics thermodynamics refrigerators applications pump diagram cycle carnot air system figure graph transfer work chapter indicated shows circleHeat pump thermodynamics sciencelearn nz tweet What is vapor-compression cycleAbout simple heat pump (thermodynamics). An artifact of the second law of thermodynamics is the ability to heat an interior space using a heat pump. If so, there is now net work into the system and net heat out of the system. The refrigerant is The log p-h diagram shows a cycle for a mechanical heat pump. For instance, in the Rankine cycle, which is crucial in power generation, you might calculate efficiency by tracing paths on the H-S diagram that represent different parts of the cycle, such as the expansion in the turbine and the compression in the pump. a) W < 7 kW b) W = 7 kW c) W > 7 kW This is what you’d need with an electric blanket A Carnot heat pump (or Carnot refrigerator) is a reverse Carnot heat engine, that absorbs heat from a cold thermal reservoir and transfers it to a warmer thermal reservoir. But, we still need a measure of how effective a refrigeration/heat pump cycle is at using work to produce heat transfer. Draw a diagram representing the heat pump system showing the flow of energy and source and sink temperatures and determine the following: The maximum possible Coefficient of Performance of a hot water heater (COP HW) that could be obtained by a reversible heat pump. Jan 25, 2023 · Refrigerators amd Heat Pumps: Know everything about its meaning, thermodynamics, components, diagram, working, etc. Mar 12, 2024 · Example \(\PageIndex{1}\): The Best COP hp of a Heat Pump for Home Use. A ground source heat pump (“GSHP”) or geothermal heat pump is a heating/cooling system for houses that transfers heat into or out of the ground using a heat pump, utilizing the relatively stable temperature of the earth throughout the seasons. May 11, 2020 · Welcome to our ‘Heat Pump Knowledge Series’, a 5-part series on heat pump essentials, with new episodes releasing on every Monday! This series is delivered by Dr. 3*F). ideal heat pump require to maintain a constant inside temperature? Solution Hot reservoir at Th Cold reservoir at Tc Qh Qc Heat W pump Heat leak ≡ − = 258 7000(1 ) 836 / 293 W J s Beware: Real heat pumps are not nearly ideal, so the advantage is smaller. As shown in Fig. 8. 7 is a schematic diagram of a thermal pump. There are two ways to tell a heat engine from a heat pump/refrigerator 1) If it is a cycle (returns to the place it starts on a PV diagram) if it progresses clockwise then it is a heat engine, counter-clockwise is a heat pump/refrigerator. and 6CE= 1000 W/K = const. Experiment #2: Operation of the Equipment as a Heat Pump While operating as a Heat Pump, heat is removed from a cold source at or below ambient temperature (the blue water cooled evaporator) and transferred to a sink (the red water cooled condenser) above ambient temperature. The heating system uses the air as heat carrier flowing in a loop between the condenser and the heated space. The one shown here is based on a Carnot (reversible) engine. Heat Pumps’ Thermodynamics Information. surroundings to a higher temperature building. 2. The former of these is negative Oct 19, 2023 · The aim of this paper is to develop a thermodynamic model for a water-to-water heat pump using propane as refrigerant. Fig. 5. In this heat pump energy flow diagram: T h is the temperature of the heat pump’s working fluid (vapour). While a refrigerator is designed primarily for cooling and preserving perishable items, a heat pump serves a dual purpose of both heating and cooling. We first consider a refrigerator (Figure 4. The directions of W , Q h , and Q c are opposite what they would be in a heat engine. A heat pump used to warm a home must employ a cycle that produces a working fluid at temperatures greater than typical indoor temperature so that heat transfer to the inside can take place. A household refrigerator removes heat from A heat pump cycle Ts diagram can help in understanding and improving the efficiency of the heat transfer process within the heat pump system. A ground source heat pump uses pipes buried in the soil. 1 4. A Python-based code for modeling the thermodynamics of the vapor compression cycle applied to residential heat pumps Rebecca Allena,*, Eirik Svortevik a, Henrik Bergersen aOslo Metropolitan University, Norway *rebeccaa@oslomet. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright interested in the heat energy removed from a low-temperature space, the device is called a refrigerator. The above diagram shows Q H amount of heat is supplied and when work is done, Q L amount of heat is rejected. 27 A simple heat pump has four basic components: (1) condenser, (2) expansion valve, (3) evaporator, and (4) compressor. For home cooling, a heat pump reverses this process and heat is extracted from the indoor air and expelled to the outside, just like a refrigerator or air conditioner, thereby making the inside air cooler. A refrigerator (or heat pump) absorbs heat \(Q_c\) from the cold reservoir at Kelvin temperature \(T_c\) and discards heat \(Q_h\) to the hot reservoir at Kelvin temperature \(T_h\) while work W is done on the engine’s working substance, as shown by the arrow pointing toward the system in the figure. which transfer heat from one place to another. Undersized or oversized heat pumps can lead to inefficiencies and decreased performance. In its most basic form, a vapor-compression refrigeration system [see Van Wylen (1985)] consists of an evaporator, a compressor, a condenser, a throttling device which is usually an expansion valve or capillary tube and the connecting tubing. Thermal pumps are either refrigerators or heat pumps, depending on what the device is used for. The energy flow in a heat pump system (Source: own elaboration) As it was mentioned above, the task of a compression heat pump is to transport heat energy from a low temperature level to a high temperature level (Fig. (b) diagram for a Carnot cycle similar to that in (Figure) but reversed, following path ADCBA. May 22, 2019 · Heat Pump – How does it work Heat Pump, Refrigerator, Air Conditioner – basic principle of operation. Applying the first law of thermodynamics to the heat pump cycle, we can derive Space heating: Heat pump is used to heat an enclosed area such as a workspace, greenhouses, and houses. The most common refrigeration cycle is the vapor compression cycle, which models systems using refrigerants that change The work required to operate the heat pump is denoted by W. An air source heat pump is likely to have a fan coil unit such as that shown in Figure 34(b). 5 °C (-55. This means we want our low and high pressures to be 93 and 333 psi, respectively. The Carnot cycle has been used for power, but we can also run it in reverse. Whether you’re driving a car, enjoying the warmth of your heating system in your bedroom, or drinking a glass of chilled wine, you’re experiencing the results of thermodynamics in action. Temperature–entropy diagram of the vapor-compression cycle. 7. Heat pumps are commonly used to heat homes by running your home AC in reverse. To determine Q E and W, it is necessary to know how the heat is produced (i. As with heat pumps, work input is required for heat transfer of energy from cold to hot. The loop consists of four main processes: compression, condensation, expansion, and evaporation. The operating principle of the refrigeration cycle was described mathematically by Sadi Carnot in 1824 as a heat engine. 4 Refrigerators and Heat Pumps. bnvfzbkimqqzkcyovybcphueituquuhnizennxgyywjhwlqshwjxtoo