Recently, there is growing demand for energy saving technologies in buildings due to global warming and environmental impact issue. As a result to this, energy-efficient technologies are becoming more popular amongst researchers and designers. In this regards, to fulfil energy conservation demands, researchers have focused on the development of advance heat or energy recovery with energy-efficient ventilation system. The aim of this paper is to review heat or energy recovery technologies for building applications. The reviews were discussed according to the concept and classification of heat or energy recovery based on types and flow arrangement. The developments of these technologies in integrated energy-efficient system such as mechanical and passive ventilation, air conditioning, dehumidification and photovoltaic panel have also been presented.

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Review on heat recovery technologies for building applications

Advancements into the computational studies have increased the development of heat pipe arrangements, displaying multiphase flow regimes and highlighting the broad scope of the respective technology for utilization in passive and active applications. The purpose of this review is to evaluate current heat pipe systems for heat recovery and renewable applications utility. Basic features and limitations are outlined and theoretical comparisons are drawn with respect to the operating temperature profiles for the reviewed industrial systems. Working fluids are compared on the basis of the figure of merit for the range of temperatures. The review established that standard tubular heat pipe systems present the largest operating temperature range in comparison to other systems and therefore offer viable potential for optimization and integration into renewable energy systems.

A review of heat pipe systems for heat recovery and renewable energy applications

Heat pipe heat exchangers and heat sinks: Opportunities, challenges, applications, analysis, and state of the art

The waste heat recovery by heat pipes is accepted as an excellent way of saving energy and preventing global warming. This paper is a literature review of the application of heat pipes heat exchangers for the heat recovery that is focused on the energy saving and the enhanced effectiveness of the conventional heat pipe (CHP), two-phase closed thermosyphon (TPCT) and oscillating heat pipe (OHP) heat exchangers. The relevant papers were allocated into three main categories, and the experimental studies were summarized. These research papers were analyzed to support future works. Finally, the parameters of effectiveness of the CHP, TPCT and OHP heat exchangers were described. This review article provides additional information for the design of heat pipe heat exchangers with optimum conditions in the heat recovery system.

A review of the applications of heat pipe heat exchangers for heat recovery

In this paper, a comprehensive review on building applications of heat recovery systems is presented The review is given as a clear and understandable summary of the previous works The review covers detailed description of heat recovery systems with working principle and system components, current typical heat recovery technologies including the building applications, theoretical, experimental and simulation works carried out for different heat recovery technologies and findings from thermodynamic performance assessment Moreover, environmental impacts of heat recovery systems are evaluated Future scenarios for heat recovery technologies including some recommendations are also considered in the study It is concluded from the results that the heat recovery systems are very promising to mitigate the fuel consumption amounts of buildings Therefore, they can remarkably contribute in reducing greenhouse gas emissions in the atmosphere

A comprehensive review of heat recovery systems for building applications

Heat pipe heat exchanger for heat recovery in air conditioning

Heat transfer experiments were conducted to investigate the thermal performance of air cooling through mini-channel heat sink with various configurations. Two types of channels have been used, one has a rectangular cross section area of 5 × 18 mm2 and the other is triangular with dimension of 5 × 9 mm2. Four channels of each configuration have been etched on copper block of 40 mm width,30 mm height, and 200 mm length. The measurements were performed in steady state with air flow rates of 0.002 - 0.005 m3/s, heating powers of 80 - 200 W and channel base temperatures of 48°C, 51°C, 55°C and 60°C. The results showed that the heat transfer to air stream is increased with increasing both of air mass flow rate and channel base temperature. The rectangular channels have better thermal performance than trian- gular ones at the same conditions. Analytical fin approach of 1-D and 2-D model were used to predict the heat transfer rate and outlet air temperature from channels heat sink. Theoretical results have been compared with experimental data. The predicted values for outlet air temperatures using the two models agree well with a deviation less than ±10%. But for the heat transfer data, the deviation is about +30% to –60% for 1-D model, and –5% to –80% for 2-D model. The global Nusselt number of the present experimental data is empirically correlated as with accuracy of ±20% for and compared with other literature correlations.

/pdf/air-cooling-of-mini-channel-heat-sink-in-electronic-devices-1oxuso0lkx.pdf

Air Cooling of Mini-Channel Heat Sink in Electronic Devices

Two modifications of solar water distillers using cement and aluminum absorbers are presented experimentally. The first modification uses separated condenser to purge vapor from the cement absorber distiller to increase the condensation, while second modification uses a plate thermosyphon charged with acetone installed on the bottom of the water basin in the aluminum absorber distiller to increase input energy to the distiller, thus increasing water vaporization and condensation. The optimum tilted angle of the glazing surface calculated to between 10 to 20° at latitude angle of 30°. The daily productivity of the cement absorber distiller was 2.08 L/ (m2.day) and increased by percentage of 18% using the separated condenser and the overall efficiency being increased from 35% to more than 48%. For the aluminum absorber distiller the average daily productivity was 2.96 L/(m2.day) and increased to 3.49 L/(m2.day) using plate thermosyphon with the overall efficiency being increased from 50% to more than 65%.  

	 

	Key words: Solar distiller, cement absorber, auxiliary condenser, aluminum absorber.

Thermosyphon solar water distiller of cement and aluminum absorber with auxiliary condenser

Two modifications of solar water distiller using cement and aluminum absorber are presented experimentally. The water basin of two modification s was constructed as a set of U channels section. The first modification used separated condenser to purg e water vapor from the cement absorber to increase th e condensation. The second modification used plate thermosyphon to increase the input energy to distil ler from bottom, thus increasing the water vaporization and condensation. The optimum tilted angle of glazi ng surface was obtained theoretically between 10~20 o at

Thermosyphon solar water distiller for remote and arid areas

Heat transfer experiments were conducted to investigate the thermal performance of air cooling through mini-channel heat sink with various configurations. Two types of channels have been used, one has a rectangular cross section area of 5×18 mm 2 and the other is triangular with dimension of 5×9 mm 2 . Four channels of each configuration have been etched on copper block of 40 mm width, 30 mm height, and 200 mm length. The measurements were performed in steady state with air flow rates of 0.002-0.005 m 3 /s, heating powers of 80-200 W and channel base temperatures of 48, 51, 55 and 60 °C. The results showed that the heat transfer to air stream is increased with increasing both of air mass flow rate and channel base temperature. The rectangular channels have better thermal performance than triangular ones at the same conditions. Analytical fin approach of 1-D and 2-D model were used to predict the heat transfer rate and outlet air temperature from channels heat sink. Theoretical results have been compared with experimental data. The predicted values for outlet air temperatures using the two models agree well with a deviation less than ± 10 %. But for the heat transfer data, the deviation is about + 30% to 60% for 1-D model, and - 5% to - 80% for 2-D model. The global Nusselt number of the present experimental data is empirically correlated as w H

Mostafa A. Abd El-Baky

Papers

Heat pipe heat exchanger for heat recovery in air conditioning

Air Cooling of Mini-Channel Heat Sink in Electronic Devices

Thermosyphon solar water distiller of cement and aluminum absorber with auxiliary condenser

Thermosyphon solar water distiller for remote and arid areas

An Experimental Investigation On Air Cooling Of Mini- channels Heat Sink