scholarly journals Heat Exchanger Design and System Balance of an Air Source Heat Pump/Chiller Using Brazed Plate Heat Exchangers

1997 ◽  
Author(s):  
Changiz Tolouee
Keyword(s):  
Heat Exchanger ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Operating Conditions ◽  
Hot Water ◽  
Pump Efficiency ◽  
Plate Heat ◽  
Air Source Heat Pump ◽  
Water Side ◽  
Brazed Plate Heat Exchangers

Air Source heat pump/chiller is used to provide chilled water for cooling and hot water for heating purposes. This is one investment for both applications with no requirement for boiler and fuel with the advantage of heat pump efficiency. In this paper we are going to analyse both air side and water side heat exchangers used in air source heat pump/chiller with special attention and emphasis on brazed plate heat exchanger which is used in refrigerant to water side of this unit in order to achieve optimum performance in both the heat pump and chiller operations. Due to compactness of brazed plate heat exchangers it is very important to balance system volume in both operating conditions which will also be examined in this paper.

An Experimental Study on the Influence of Flow Maldistribution on the Pressure Drop Across a Plate Heat Exchanger

2004 ◽  
Vol 126 (4) ◽  
pp. 680-691 ◽  
Author(s):  
B. Prabhakara Rao ◽  
Sarit K. Das
Keyword(s):  
Experimental Study ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Plate Heat Exchanger ◽  
Operating Conditions ◽  
Plate Heat ◽  
General Flow ◽  
Proper Design ◽  
Flow Maldistribution

A detailed experimental study on flow maldistribution from port to channel of a plate heat exchanger is presented. In general, flow maldistribution brings about an increase in pressure drop across the heat exchanger. This increase is found to depend on flow rate, number of channels and port size. Experiments show that analytical predictions of pressure drop including maldistribution effect are quite accurate for practical purposes. The results indicate that under identical conditions, maldistribution is more severe in Z-type plate heat exchanger compared to U type. Experiments are also carried out under non-isothermal realistic operating conditions, which show increased flow maldistribution at elevated temperature. Finally predictions are made for industrial plate heat exchangers, which show the limitation of adding additional plates beyond a certain limit. An insight to the physical aspects of maldistribution and its possible reduction through proper design strategy is also indicated.

Numerical Evaluation of Plate Heat Exchanger Performance in Geothermal District Heating Systems

1996 ◽  
Vol 210 (2) ◽  
pp. 139-147 ◽  
Author(s):  
T Karlsson
Keyword(s):  
Heat Exchanger ◽  
Mass Flow ◽  
Heat Exchangers ◽  
District Heating ◽  
Hot Water ◽  
Geothermal Systems ◽  
Geothermal Resources ◽  
Heating Systems ◽  
Plate Heat ◽  
Flow Approximation

This paper describes the performance of plate heat exchangers in residential water radiator heating systems receiving their heat from geothermal resources. Radiator theory is reviewed and determination of annual hot water requirements for space heating is discussed. Performance evaluation is made of plate heat exchangers and results obtained by means of two equations commonly used for this purpose, the Sieder–Tate and the Dittus–Boelter equations, compared to results obtained with a simplified equation where heat transfer in the heat exchanger is assumed to depend only on the fluid mass flow on both sides. It is found that for prevailing temperature ranges in Icelandic geothermal systems the mass flow approximation gives results very close to those determined by the more complicated conventional equations.

scholarly journals Impact of Compressor Drive System Efficiency on Air Source Heat Pump Performance for Heating Hot Water

2020 ◽  
Vol 12 (24) ◽  
pp. 10521
Author(s):  
Mariusz Szreder ◽  
Marek Miara
Keyword(s):  
Heat Pump ◽  
Air Temperature ◽  
Heating System ◽  
Operating Conditions ◽  
Drive System ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Air Source Heat Pump ◽  
Heating Capacity ◽  
The Impact

A standard Polish household with a central heating system powered by a solid fuel furnace was chosen as a case study. The modular Air Source Heat Pump (ASHP) was used to heat the hot water outside the heating season. In this article comparative studies of the impact of the compressor drive system used on the energy efficiency of the heat pump have been carried out in operating conditions. The ASHP heating capacity and coefficient of performance (COP) were determined for the outside air temperature in the range from 7 to 22 °C by heating the water in the tank to a temperature above 50 °C. For the case of a fixed speed compressor, average heating capacity in the range 2.7−3.1 kW and COP values in the range 3.2−4.6 depending on the evaporator supply air temperature were obtained. Similarly, for the inverter compressor, the average heating capacity in the range of 2.7−5.1 kW was obtained for the frequency in the range of 30–90 Hz and COP in the range 4.2−5.7, respectively. On cool days, the average heating capacity of the heat pump decreases by 12%. For the simultaneous operation of two compressors with comparable heating capacity, lower COP values were obtained by 20%.

scholarly journals EXPERIMENTAL INVESTIGATION OF AIR-SOURCE HEAT PUMP IN DIFFERENT REAL OPERATIONAL CONDITIONS FOR HEATING DISTINCTIVE REGIMES

2020 ◽  
pp. 087
Author(s):  
Goran Vuckovic ◽  
Mića Vukić ◽  
Mirko Stojiljković ◽  
Marko Ignjatović
Keyword(s):  
Low Temperature ◽  
Heat Pump ◽  
Operating Conditions ◽  
Hot Water ◽  
Maximum Temperature ◽  
Water Heating ◽  
Pump Operation ◽  
Domestic Hot Water ◽  
Air Source Heat Pump ◽  
Heating Mode

In a time of permanent care for environmental protection, energy consumption and conservation of resources, heat pumps are becoming increasingly important as a technology for reducing greenhouse gas emissions while preservation thermal comfort in build environment. This paper presents the experimental results of air-source heat pump in different real operating conditions, as follows: for space heating by low-temperature underfloor heating when the supply water temperature was set at 38°C, or for domestic hot water heating in the storage tank volume of 180 liters at a temperature of 46°C. In the low-temperature underfloor heating mode, the efficiency of the air-source heat pump could be increased if the maximum temperature at the end of the compression process and the condensing temperature were reduced in the initial phase of the heat pump operation. In the domestic hot water heating mode, the efficiency of the air-source heat pump could be increased if the maximum condensation temperature in the final phase of the heat pump operation was limited.

Experimental Characterization of a Natural Convection Heat Exchanger for Solar Domestic Hot Water Systems

Solar Energy ◽  
2006 ◽  
Author(s):  
Cynthia A. Cruickshank ◽  
Stephen J. Harrison
Keyword(s):  
Natural Convection ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Computational Models ◽  
Operating Conditions ◽  
Hot Water ◽  
Test Method ◽  
Convection Flow ◽  
Convection Heat ◽  
Domestic Hot Water

To predict the long-term performance of solar domestic hot water (SDHW) systems requires computational models that can characterize the systems under a range of operating conditions. The development of detailed fundamental models that suitably describe the operation of systems with natural convection heat exchangers is, however, difficult and time consuming. The fact that the natural convection flow through the heat exchanger is intrinsically self-controlling and temperature dependent complicates the analysis. One approach to modeling this type of system is to use performance characteristics, empirically derived from experimental data, to predict the performance of the heat exchanger under typical operating conditions. Unfortunately, a significant number of tests may be required to characterize the full operation of the device. This paper presents a simplified test method that was developed to allow pre-configured SDHW systems that use natural convection heat exchangers, to be characterized. The results of this test method produce performance coefficients for simple empirical expressions that describe the fluid flow and heat transfer in the heat-exchange loop. These empirically derived coefficients are an input to a general simulation routine that allows overall system performance to be determined for various loads and climatic conditions. In this paper, data is presented for a typical heat exchanger under a range of operational conditions.

scholarly journals Experimental investigation of an Air Source Heat Pump

2019 ◽  
Vol 85 ◽  
pp. 01011
Author(s):  
Mugurel Florin Tălpigă ◽  
Florin Iordache ◽  
Eugen Mandric
Keyword(s):  
Experimental Investigation ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Plate Heat Exchanger ◽  
Secondary Circuit ◽  
Plate Heat ◽  
Air Source Heat Pump ◽  
Current Consumption ◽  
Working Parameters ◽  
Pump Compressor

An experimental investigation were driven to catch all working parameters of an Air Source Heat Pump such as temperature differences between refrigerant working states and evaporator respectively condenser environment temperatures. Heat Pump compressor were monitored to know inlet and outlet refrigerant temperatures to build working diagram of the heat pump in heating configuration. At condenser, a plate heat exchanger is used to discharge the energy from refrigerant to water, liquid used in secondary circuit. Heat exchanger temperatures of refrigerant and water were monitored to drive the working diagram of the heat exchanger equipment. Current consumption of Heat Pump were registered together with heat exchanger secondary circuit temperature differences and his water flow to estimate Seasonal Performance Factor during experiment.

Combined Experimental and Simulation (CFD) Analysis on Thermal Performance of Plate Heat Exchanger Using Kerosene as Working Fluid

2009 ◽  
Vol 4 (1) ◽  
Author(s):  
K.Dheena Thayalan ◽  
Ponnusamy Kalaichelvi
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Plate Heat Exchanger ◽  
Hot Water ◽  
Flow Rates ◽  
Plate Heat ◽  
Cold Fluid ◽  
Experimental Runs

The plate heat exchanger exhibits excellent heat transfer characteristic, which allows a very compact design with ease of maintenance and modification of heat transfer area by adding (or) removing plates. Constructional parameters such as flow path, trough angle and corrugation can affect the performance of plate heat exchangers by altering effectiveness (?) and number of transfer unit (NTU). Especially plate heat exchangers play a vital role in petroleum industries for wide range of temperature application. Hence, it was proposed to choose kerosene as cold fluid and hot water as hot fluid in this present investigation. A vertical type of plate heat exchanger, in which flow pattern is maintained as co-current, has been used to conduct the experimental runs. The numbers of plates in the plate heat exchanger used in the present study are 10. The number of flow channels (space maintained between two consecutive channels) allocated for both fluids are 9. Experimental runs have been conducted for different combinations of hot fluid flow rates and cold fluid flow rates for single phase flow, in which hot water is considered as hot streams and kerosene as cold fluid. The thermal performance of plate heat exchanger has been analyzed based on calculated parameters using experimental data set. A similar corrugated plate heat exchanger model having the same dimensions as that of the experimental one was developed with aid of CFD tool. The model was simulated at different operating conditions and compared with experimental results. The simulated results are in good agreement with experimental data. The percentage deviation between experimental results and simulation results for over all heat transfer coefficient is less than ±6%.

Simulative Study on Solar-Assisted Air Source Heat Pump System

2013 ◽  
Vol 671-674 ◽  
pp. 2141-2144 ◽  
Author(s):  
Qiang Wang ◽  
Feng Zhen Liu ◽  
Li Jun Hou ◽  
Jian Hua Gao
Keyword(s):  
Heat Pump ◽  
Operating Conditions ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Pump Unit ◽  
Pump System ◽  
Heat Pump System ◽  
Air Source Heat Pump ◽  
Heat Pump Unit ◽  
The Stability

A solar assisted air source heat pump unit is designed. The mathematical model of the unit is established and two hybrid operating conditions of the system are simulated. The simulative studying results shows that in winter the solar assisted air source heat pump unit can make full use of solar energy and the coefficient of performance (COP) of air source heat pump can be improved. In summer the cooling heat of air source heat pump could be recovered to improve the stability of solar hot water collector and the COP of the air source heat pump unit is greatly improved. The performance of solar assisted air source heat pump unit is better than that of with no solar assisted air source heat pump.

Application of Equipartition of Entransy Loss Principle in Heat Exchangers

2012 ◽  
Vol 629 ◽  
pp. 699-703
Author(s):  
Chun Sheng Guo ◽  
Wen Jing Du ◽  
Lin Cheng
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Optimization Design ◽  
Loss Rate ◽  
Plate Heat Exchanger ◽  
Loss Minimization ◽  
Plate Heat ◽  
Entransy Loss ◽  
Heat Exchanges ◽  
Minimization Approach

The entransy loss minimization approach for the heat exchanger optimization design was established by Guo Z Y; the study based Guo Z Y’s works, found relationship between the entransy loss uniformity and the heat exchanger performance and the expression of the local entransy loss rate for heat convection was derived, numerical results of the heat transfer in a chevron plate heat exchanger and helix baffle heat exchanger show that the larger entransy loss uniformity factor appear in about Re=2000 and the entransy loss uniformity factor of chevron plate heat exchanges higher than helix baffle one.

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