The heat pump experiment was performed to collect temperature, pressure, flow rate, andpower data from the Hylton Air and Water Heat Pump. These data were used to calculateheat transfer in the system and overall performance values of the heat pump system.
The experiment began by adjusting the heat pump to the correct operatingparameters. The amount of power required to operate the compressor was then recorded.Temperature, pressure, and mass flow rate were determined for both refrigerant and water atmultiple locations on the heat pump. These values were read from either a digital display oran analog display depending on what was to be measured.
Experiment 1: Refrigeration and Mechanical Heat Pump Experiment.pdf
The data recorded was then used, along with a pressure-enthalpy diagram and atemperature table of R-134 refrigerant, to determine the enthalpy. Knowing the enthalpy ateach stage of the heat pump cycle it was possible to determine the heat transfer in theevaporator, condenser, and compressor. The calculated enthalpies were analyzed anddetermined to reasonable for the operating conditions. Slight differences can be contributedto a small amount of heat being lost to the surroundings of the heat pump. There may alsohave been minor errors in taking readings from the analog equipment.
The purpose of the heat pump experiment was to determine the performance values of theHylton Air and Water Pump System. This was done by taking readings at the four basiccomponents of the system: the compressor, condenser, expansion valve, and evaporator. Thereadings were taken so it could be determined where work was put in and where heat wasadded or removed. These values allowed for the calculation of the heat pump efficiency andthe coefficient of performance.
Heat pumps are devices that move heat in a direction that is opposite of spontaneous flow.This means that a heat pump moves heat from a location with a cooler temperature to anotherlocation with a warmer temperature. The term heat pump can be used to describe a devicethat heats or cools a given location. Heat pumps can be used in a variety of applicationsincluding refrigeration, air conditioning, and heating. The function of heating or cooling isdetermined by the conditions of the environment and where the heat is released by the heatpump.
Any heat pump has an ideal coefficient of performance (COP). But in reality, the coefficientof performance is less than the ideal value, and this is because of multiple reasons that causeinaccuracy or losses in the system, such as mechanical or electrical losses in the fan or thecompressor, or errors in measuring devices, especially when acquiring the wet bulbtemperature (WBT).
A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes.[1] The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact.[2] They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum refineries, natural-gas processing, and sewage treatment. The classic example of a heat exchanger is found in an internal combustion engine in which a circulating fluid known as engine coolant flows through radiator coils and air flows past the coils, which cools the coolant and heats the incoming air. Another example is the heat sink, which is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant.[3]
Another type of heat exchanger is the plate heat exchanger. These exchangers are composed of many thin, slightly separated plates that have very large surface areas and small fluid flow passages for heat transfer. Advances in gasket and brazing technology have made the plate-type heat exchanger increasingly practical. In HVAC applications, large heat exchangers of this type are called plate-and-frame; when used in open loops, these heat exchangers are normally of the gasket type to allow periodic disassembly, cleaning, and inspection. There are many types of permanently bonded plate heat exchangers, such as dip-brazed, vacuum-brazed, and welded plate varieties, and they are often specified for closed-loop applications such as refrigeration. Plate heat exchangers also differ in the types of plates that are used, and in the configurations of those plates. Some plates may be stamped with "chevron", dimpled, or other patterns, where others may have machined fins and/or grooves.
The refrigerant is boiled by the heat source in the evaporator to produce super-heated vapor. This fluid is expanded in the turbine to convert thermal energy to kinetic energy, that is converted to electricity in the electrical generator. This energy transfer process decreases the temperature of the refrigerant that, in turn, condenses. The cycle is closed and completed using a pump to send the fluid back to the evaporator.
One of the widest uses of heat exchangers is for refrigeration and air conditioning. This class of heat exchangers is commonly called air coils, or just coils due to their often-serpentine internal tubing, or condensers in the case of refrigeration, and are typically of the finned tube type. Liquid-to-air, or air-to-liquid HVAC coils are typically of modified crossflow arrangement. In vehicles, heat coils are often called heater cores.
On the liquid side of these heat exchangers, the common fluids are water, a water-glycol solution, steam, or a refrigerant. For heating coils, hot water and steam are the most common, and this heated fluid is supplied by boilers, for example. For cooling coils, chilled water and refrigerant are most common. Chilled water is supplied from a chiller that is potentially located very far away, but refrigerant must come from a nearby condensing unit. When a refrigerant is used, the cooling coil is the evaporator, and the heating coil is the condenser in the vapor-compression refrigeration cycle. HVAC coils that use this direct-expansion of refrigerants are commonly called DX coils. Some DX coils are "microchannel" type.[5]
The main advantage of the SHE is its highly efficient use of space. This attribute is often leveraged and partially reallocated to gain other improvements in performance, according to well known tradeoffs in heat exchanger design. (A notable tradeoff is capital cost vs operating cost.) A compact SHE may be used to have a smaller footprint and thus lower all-around capital costs, or an oversized SHE may be used to have less pressure drop, less pumping energy, higher thermal efficiency, and lower energy costs.
Small-diameter coil technologies are becoming more popular in modern air conditioning and refrigeration systems because they have better rates of heat transfer than conventional sized condenser and evaporator coils with round copper tubes and aluminum or copper fin that have been the standard in the HVAC industry. Small diameter coils can withstand the higher pressures required by the new generation of environmentally friendlier refrigerants. Two small diameter coil technologies are currently available for air conditioning and refrigeration products: copper microgroove[26] and brazed aluminum microchannel.[citation needed] 2ff7e9595c
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