Nearly 70% of the energy produced from automotive engines is released to the atmosphere in the form of waste energy. The recovery of this energy represents a vital challenge to engine designers primarily when a thermoelectric generator (TEG) is used, where the availability of a continuous, steady-state temperature and heat flow is essential. The potential of semi-truck engines presents an attractive application as many coaches and trucks are roaming motorways at steady-state conditions most of the time. This study presents an analytical thermal design and an experimental validation of the TEG system for waste heat recovery from the exhaust of semi-truck engines. The TEG system parameters were optimized to achieve the maximum power output. Experimental work was conducted on a specially constructed setup to validate the analytically obtained results. Both analytical and experimental results were found to be in good agreement with a marginal deviation, indicating the excellent accuracy of the effective material properties applied to the system since they take into account the discrepancy associated with the neglection of the contact resistances and Thomson effect.

The present article reports on the design, modeling and parametric optimization of a thermoelectric cooling system for electronics applications. An analytical model based on energy equilibrium is developed for cooling a microprocessor using a thermoelectric module with an air-cooled finned heat sink. The proposed analytical model is validated by experimental measurements and by comparison with detailed 3D numerical simulations. Estimation of effective material properties of the thermoelectric module using manufacturer-reported performance characteristics is found to reduce the uncertainty in the calculation of module input power as compared to experimental measurements. A parametric optimization of the thermoelectric module and heat sink is carried out to maximize the coefficient of performance (COP) and achieve the required cooling capacity of the microprocessor. The effectiveness of the proposed methodology is demonstrated for cooling current high power microprocessors. At a constant input current, the cooling capacity and COP of the thermoelectric cooling system increase with increasing thermoelectric module geometric ratio. Furthermore, at a constant geometric ratio, the cooling power increases with increasing input current to reach a maximum value and then decreases. The present study highlights the importance of designing and fabricating high-performance thermoelectric cooler modules with optimum parameters for cooling specific electronic components. The results indicate that the cooling capacity can be increased by ~70% using thermoelectric modules with optimized parameters as compared to using non-optimized commercially available thermoelectric modules.

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The present article reports on the analysis of waste heat and condensate recovery from residential air conditioning (AC) units in different climatic regions in Saudi Arabia. Simulation results obtained using a transient dynamic model show that significant amounts of waste heat and water condensate are rejected to the environment in hot and humid climate regions. A multi-generation system for simultaneous cooling and pure water production using condensate and waste heat recovery is designed and implemented in TRNSYS environment. A refrigerant to water de-superheater is introduced after the compressor to extract energy from the high temperature superheated refrigerant gas for heating saline water that is used as a feed to drive an air gap membrane desalination unit. The production of pure water is analyzed for both batch and continuous cooling modes of the membrane desalination unit. The amount of pure water production shows the potential of proposed system to supply pure water requirements in hot and humid climates in Saudi Arabia. The monthly average coefficient of performance of multi-generation residential AC units with continuous cooling of desalination unit is shown to be improved by ~6.61%. The monthly average gained output ratio of membrane desalination unit is higher than 1.14.