Wind Evaporator Heat Pumps—Part I: Test Methods

1992 ◽  
Vol 114 (4) ◽  
pp. 281-285 ◽  
Author(s):  
P. F. Monaghan ◽  
D. P. Finn ◽  
J. M. O’Reilly
Keyword(s):  
Heat Transfer ◽  
Energy Efficient ◽  
Heat Transfer Performance ◽  
Field Performance ◽  
Weather Conditions ◽  
Heat Pumps ◽  
Test Methods ◽  
Finned Tube ◽  
Test Facility ◽  
Wide Range

Wind evaporators are alternative evaporators for air source heat pumps which rely on wind-driven or natural convection to move air across the heat transfer surfaces. It is believed that, in certain climates, wind evaporators can operate satisfactorily with frost on their surfaces for extended periods of time and defrost passively during switch-off periods. If so, an active defrost cycle would be unnecessary in these climates. Wind evaporators present an opportunity for heat pumps to be less expensive, more reliable, and more energy-efficient. However, the heat transfer performance of wind evaporators varies as a result of changes in a wide range of climatic variables. To determine the technical feasibility of wind evaporators, it is necessary to test complete wind evaporator heat pumps and to compare their monitored field performance over extended periods to that of conventional heat pumps with fan-assisted, finned-tube evaporators. In this paper, a test facility which allows side-by-side testing of wind evaporator and conventional heat pumps and monitoring of weather conditions is described. The choice of measurement technique for each variable is discussed and estimates of the measurement uncertainty for each sensor are made.

Development of an Outdoor Test Facility for Wind Convectors

1990 ◽  
Vol 112 (4) ◽  
pp. 287-292 ◽  
Author(s):  
P. F. Monaghan ◽  
D. P. Finn ◽  
P. H. Oosthuizen
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Heat Pumps ◽  
Test Facility ◽  
Transfer Performance ◽  
Test Results ◽  
Transfer Coefficients ◽  
Transfer Rates ◽  
Heat Transfer Coefficients ◽  
Outdoor Test

This paper deals with measurement of heat transfer performance of wind convectors, an alternative air source evaporator system for heat pumps. An automatically controlled and monitored outdoor wind convector test facility that is capable of measuring heat transfer rates and overall heat-transfer coefficients to within ± 5 percent measurement uncertainty for up to three wind convectors has been designed, built, and tested. Data on air temperature and humidity, solar radiation, and wind speed and direction are simultaneously collected. The choice of measurement technique for each variable and an error analysis for each sensor is discussed. Typical graphical test results are presented.

A Focus on the Literature Review of Nanorefrigerants

2014 ◽  
Author(s):  
Ahmet Selim Dalkılıç ◽  
Melih Aktaş ◽  
Ali Celen ◽  
Alican Çebi ◽  
Omid Mahian ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Air Conditioning ◽  
Base Fluid ◽  
Heat Transfer Performance ◽  
Heat Pumps ◽  
Wide Range ◽  
The Common ◽  
Air Conditioning Systems ◽  
Passive Techniques

The heat transfer performance of various thermal devices can be augmented by active and passive techniques. One of the passive techniques is the addition of nanoparticles had the size of 1 and 100 nanometers to the common heat transfer so that the thermal transport properties of the prepared suspension called nanofluid will be enhanced compared to the base fluid. Nanorefrigerants as a special type of nanofluids which are mixtures of nanoparticles and refrigerants have a wide range of applications in diverse fields such as refrigeration, air conditioning systems and heat pumps. In this study, the missing points on this new method are also indicated regarding the lack of studies on the determination of physical properties of nanorefrigerants and the flow of nanoparticles.

Heat Transfer Testing of Enhanced Finned-Tube Bundles Using the Single-Blow Technique

2003 ◽  
Author(s):  
J. E. O’Brien ◽  
M. S. Sohal ◽  
P. C. Wallstedt
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Transfer Performance ◽  
Performance Testing ◽  
Finned Tube ◽  
Test Facility ◽  
Transfer Performance ◽  
Number Range ◽  
Longitudinal Vortices ◽  
Tube Bundles

A single-blow test facility has been developed at the INEEL for pressure-drop and heat transfer performance testing of heat exchanger finned-tube bundles. Initial testing in the facility has been aimed at evaluating several enhanced heat transfer geometries to be used with individually finned tubes in which winglet vortex generators have been punched into the fin surfaces at specific locations. The winglets interact with the air flow to create longitudinal vortices that enhance fin-surface heat transfer performance with minimal increase in pressure drop. Results of two initial studies indicate heat transfer enhancement levels of 20–30% across the tested Reynolds number range (100–3000), with an increase in pressure drop of only 4–12%, over the same range.

Enhanced Condensation Heat-Transfer on Mini or Low Fin Tubes

2006 ◽  
Author(s):  
Adrian Briggs
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Thermophysical Properties ◽  
Heat Transfer Performance ◽  
Three Dimensional ◽  
Transfer Performance ◽  
Transfer Enhancement ◽  
Shell Side ◽  
Wide Range ◽  
Fin Tubes

This paper presents an overview of the use of low or mini-fin tubes for improving heat-transfer performance in shell-side condensers. The paper concentrates on, but is not limited to, the experimental and theoretical program in progress at Queen Mary, University of London. This work has so far resulted in an extensive data base of experimental data for condensation on single tubes, covering a wide range of tube geometries and fluid thermophysical properties and in the development of a simple to use model which predicts the majority of this data to within 20%. Work is progressing on the effects of vapor shear and on three-dimensional fin profiles; the later having shown the potential for even higher heat-transfer enhancement.

Research on Chinese Codes and Standards of Heat Transfer Performance Testing for Heat Exchangers

2020 ◽  
Author(s):  
Bin Ren ◽  
Xiaoying Tang ◽  
Facai Ren ◽  
Jibing Wang ◽  
Bofeng Bai
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Performance Test ◽  
Heat Transfer Performance ◽  
Performance Testing ◽  
Test Methods ◽  
Transfer Performance ◽  
Factors Affecting ◽  
Nonlinear Fitting ◽  
Test Standards

Abstract Heat exchanger is a device that transfers heat between hot and cold fluids. Due to the different size and type, the actual heat transfer performance is usually not the same as the design value. Meanwhile, various heat exchangers using new types of heat transfer elements have emerged, bringing the difficulty to obtain the heat transfer performance by only theoretical calculation. Therefore, studying test methods and developing test standards for heat exchangers have become the research focus in many countries. In this paper, the basic principles of various performance test methods are firstly introduced, including Wilson plot method, equal Reynolds number method and nonlinear fitting method. Then the restrictions on the use of these methods and the factors affecting the test results are analyzed. Finally, the Chinese codes and standards of performance testing for heat exchangers are listed, including JB/T 10379-2002, GB/T 27698-2011 and TSG R0010-2019. The test methods used in GB/T 27698 are described in detail. The results show that GB 27698 mainly focus on the specification of testing systems and procedures and can test heat transfer performance of almost all types of heat exchangers in industry under different heat transfer modes. However, there are lack of formulas and methods for calculating uncertainty of testing results.

Study on Heat Transfer and Resistance Characteristics of H-Type Finned Tube

2013 ◽  
Vol 805-806 ◽  
pp. 1817-1822 ◽  
Author(s):  
Zhang Jun Wang ◽  
Zhuo Xiong Zeng ◽  
Yi Hua Xu
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Heat Transfer Performance ◽  
Euler Number ◽  
Numerical Study ◽  
Three Dimensional ◽  
Finned Tube ◽  
Comprehensive Performance ◽  
Better Than

Three-dimensional numerical study is performed for heat transfer and resistance characteristics as well as comprehensive performance of two kinds H-type (single and double) finned tube. It is found that the heat transfer and resistance characteristics as well as comprehensive performance of H-type finned tube are influenced by the Reynolds number of gas. With the growth of Reynolds number, the air-side Nusselt number rises gradually and the heat transfer performance gets better and better, whereas the air-side Euler number drops step by step until close to a fixed value. The comprehensive performances of both single H-type finned tube and double ones are weaken progressively. When Reynolds number value is same, the convective heat transfer, pressure drop, air-side Nusselt number and Euler number of single H-type finned tube are bigger than those of double ones. The single H-type finned tube expression is much better than double ones in comprehensive performance and heat transfer.

Performance of a Compact Cooling Unit Utilizing Air-Water Mist Flow

1983 ◽  
Vol 105 (1) ◽  
pp. 18-24 ◽  
Author(s):  
T. Aihara ◽  
R. Saga
Keyword(s):  
Heat Transfer ◽  
Parallel Plate ◽  
Heat Transfer Performance ◽  
Thermal Conditions ◽  
Water Mist ◽  
Transfer Performance ◽  
Cooling Unit ◽  
Wide Range ◽  
Mist Flow ◽  
Plate Channel

Performance of a new compact cooling unit for semiconductors, being composed of an atomizer, a fan, and a heat-dissipating surface with no fin, has been measured over a wide range of the mass flow rate of spray water, m˙, and the wall heat flux. The heat transfer performance of the present compact, unit with m˙ = 0 to 1.05 g/s, attains 1.8 to 20 times that of the parallel-plate channel under the same thermal conditions.

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