scholarly journals Heat Pipes Heat Exchanger for HVAC Applications

2021 ◽  
Author(s):  
Anwar Barrak
Keyword(s):  
Developing Countries ◽  
Heat Exchanger ◽  
Energy Saving ◽  
Heat Pipe ◽  
Energy Production ◽  
Engineering Applications ◽  
Condenser Section ◽  
Oscillating Heat Pipe ◽  
Wasted Heat ◽  
Wasted Energy

With increasing global demands for energy (especially in developing countries), energy production will increase, the wasted energy will increase, and the emission and pollution will increase also. That makes the researchers focus on recovering the wasted heat and enhancing the recovery devices to improve the energy-saving amount. Heat pipe technology is one of the promising methods of transfer heat efficiently between two species. There are three common types of heat pipe; conventional heat pipe, thermosyphon, and oscillating heat pipe. Each type contains three sections: evaporator, adiabatic, and condenser section. The heat pipe as a heat exchanger was investigated and experimentally used by many authors to recover the wasted energy in many engineering applications.

A Heat Recovery Device using Oscillating Heat Pipe with Circular and Elliptical Tubes

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Anwar S. Barrak ◽  
Ahmed A. M. Saleh ◽  
Zainab H. Naji
Keyword(s):  
Heat Exchanger ◽  
Energy Saving ◽  
Heat Pipe ◽  
Heat Recovery ◽  
Working Fluid ◽  
Cross Sectional ◽  
Elliptical Cross ◽  
Oscillating Heat Pipe ◽  
Comparison Results ◽  
Pipe Heat

In this study, an oscillating heat pipe heat exchanger has been used as a heat recovery device in air ductwork, and the characteristics of the thermal performance of the energy-saving were investigated by using a circular and elliptical cross-sectional tubes. An experimental study was conducted by oscillating heat pipe made from copper with an inner diameter of 3.5 mm for the conventional tube, and the major and minor axis of 4.2 and 2.2 mm for the elliptical tube. The working fluid was water with filling ratio of 50% of the total volume. The experimental data implied that the thermal effectiveness and the energy-saving highly affected by the inlet air temperature and velocity. The proposed model of the oscillating heat pipe heat exchanger possessed the effectiveness of 19.5% at 50 ºC and 0.5 m/s, and the potential energy-saving of 1117 W at 50 ºC and 2 m/s. The comparison results between the elliptical and conventional cross-sectional area of oscillating heat pipe heat exchanger indicated that the energy-saving and effectiveness enhanced by the ratio of 18%, and 14%.

scholarly journals Effect of Filling Ratio on Thermal Characteristics and Performance of a Pulsating Heat Pipe

2019 ◽  
Vol 9 (2) ◽  
pp. 3341-3345
Keyword(s):  
Heat Pipe ◽  
Thermal Characteristics ◽  
Filling Ratio ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Key Factors ◽  
Condenser Section ◽  
Oscillating Heat Pipe ◽  
Bottom Heat ◽  
And Performance

Pulsating heat pipes are complex devices for heat transfer and their optimal thermal performance depends mainly on different parameters. This work is about the thermal efficiency of a closed-loop oscillating heat pipe with a diameter of 2.0 mm and 3.0 copper tube inner and outer. For all experiments, the filling ratio (FR) was used 40%, 50 %,70%,80% and heat inputs of 20W, 40W, 60W, and 80W was provided to PHP. The position of the PHP was vertical bottom heat type. The length of evaporator, adiabatic and condenser section was maintained 52 mm,170mm,60mm. Water and benzene were selected as working fluids. From the available literature it is observed that working fluid and filling ratio are key factors in PHP's performance. The results show that the thermal resistance decreases rapidly with the increase in the heat input to 20 to 40 W., while it decreases gradually over 40 to 80W.Simulation is done in CFD and experimental data were equated to the results.

scholarly journals Thermal Performance and Energy Saving Analysis of Indoor Air–Water Heat Exchanger Based on Micro Heat Pipe Array for Data Center

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 393 ◽  
Author(s):  
Heran Jing ◽  
Zhenhua Quan ◽  
Yaohua Zhao ◽  
Lincheng Wang ◽  
Ruyang Ren ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Energy Saving ◽  
Heat Pipe ◽  
Flow Rate ◽  
Data Center ◽  
Data Centers ◽  
Air Flow ◽  
Air Flow Rate ◽  
Cold Energy

According to the temperature regulations and high energy consumption of air conditioning (AC) system in data centers (DCs), natural cold energy becomes the focus of energy saving in data center in winter and transition season. A new type of air–water heat exchanger (AWHE) for the indoor side of DCs was designed to use natural cold energy in order to reduce the power consumption of AC. The AWHE applied micro-heat pipe arrays (MHPAs) with serrated fins on its surface to enhance heat transfer. The performance of MHPA-AWHE for different inlet water temperatures, water and air flow rates was investigated, respectively. The results showed that the maximum efficiency of the heat exchanger was 81.4% by using the effectiveness number of transfer units (ε-NTU) method. When the max air flow rate was 3000 m3/h and the water inlet temperature was 5 °C, the maximum heat transfer rate was 9.29 kW. The maximum pressure drop of the air side and water side were 339.8 Pa and 8.86 kPa, respectively. The comprehensive evaluation index j/f1/2 of the MHPA-AWHE increased by 10.8% compared to the plate–fin heat exchanger with louvered fins. The energy saving characteristics of an example DCs in Beijing was analyzed, and when the air flow rate was 2500 m3/h and the number of MHPA-AWHE modules was five, the minimum payback period of the MHPA-AWHE system was 2.3 years, which was the shortest and the most economical recorded. The maximum comprehensive energy efficiency ratio (EER) of the system after the transformation was 21.8, the electric power reduced by 28.3% compared to the system before the transformation, and the control strategy was carried out. The comprehensive performance provides a reference for MHPA-AWHE application in data centers.

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