Showing papers on "Heat capacity rate published in 2014"
TL;DR: In this article, the use of flat heat pipe as an effective and low-energy device to mitigate the temperature of a battery module designed for a HEV application was investigated, and the nominal heat flux generated by the battery module was reproduced and applied to a flat heatpipe cooling system.
207 citations
TL;DR: In this article, the performance of an organic Rankine cycle (ORC) powered by medium-temperature heat sources has been evaluated for different operating conditions and design criteria, and the results show that the plant efficiency decreases as both heat source mass flow rate and temperature increase.
131 citations
TL;DR: In this article, the actual heat transfer coefficient of a phase change material (PCM) was measured experimentally with the purpose of improving the heat storage rate of an automotive coolant waste heat storage system using the latent heat of the PCM.
127 citations
TL;DR: In this paper, a closed loop Pulsating Heat Pipe (CLPHP) with four transparent glass tubes forming the adiabatic section and connected with copper U-turns in the evaporator and condenser sections is designed in order to perform comprehensive thermal-hydraulic performance investigation.
120 citations
TL;DR: In this article, a two-stage TEG model is built using the exhaust gas of an internal combustion engine (ICE) as heat source, and the results show that the absorbed heat, output power, and conversion efficiency increase significantly with increasing heat transfer coefficient up to the value of 400 Wm−m−2 K−1.
118 citations
TL;DR: In this article, a 3D numerical model for simulating vertical U-tube geothermal heat exchangers (GHEs) is presented, which uses 1D linear elements coupled with the 3D domain using the temperature field along the exterior surface of the pipe and an optimized finite element mesh.
100 citations
TL;DR: In this article, a numerical model in MODFLOW/MT3DMS of a single U-pipe in a sandy aquifer is proposed in order to investigate the two issues in a coupled approach.
99 citations
TL;DR: In this article, reversible and irreversible electrochemical heat generation rates were measured experimentally on a small commercially available C/LiFePO 4 lithium-ion battery designed for high-rate applications.
95 citations
TL;DR: In this article, the authors investigated the oscillation characteristics and the heat transfer performance of a closed-loop pulsating heat pipe (PHP) with deionized water, methanol, ethanol and acetone.
81 citations
TL;DR: In this paper, a numerical study concerning an improved heat sink for a light emitting diodes (LED) lamp operating under natural convection conditions is presented, where the main objective is to cool the LED lamp so that the lamp maximum temperature at the contact region with the heat sink is maintained below the critical temperature given by the manufacturer.
79 citations
TL;DR: In this paper, a connectionist investigation of irreversible Stirling heat pump cycles that includes both internal and external irreversibilities together finite heat capacities of external reservoirs was carried out, and three objective functions including the heating load (RH) and coefficient of performance (COP) have been simultaneously maximized, on the other hand at the same time the input power of the Stirling Heat Pump is minimized.
TL;DR: In this paper, two cases of heat exchangers (HEXs) which previously were used in exhaust of internal combustion engines (ICEs) are modeled numerically to recover the exhaust waste heat.
TL;DR: In this paper, a solid byproduct from the potash industry is tested in two different shapes to be used for industrial sensible heat recovery in high temperature, in a range of======100-200 oC.
TL;DR: In this article, the location of heat transfer pinch point in evaporator is the base of determining operating parameters of organic Rankine cycle (ORC), by which, the temperature variations both of heat source and working fluid with UA can be obtained.
TL;DR: In this article, a closed-loop pulsating heat pipe (PHP) with four types of working fluids, deionized water, methanol, ethanol and acetone, was investigated.
TL;DR: In this article, the authors presented a new technology which combines the absorption heat pump and the direct-contact heat exchanger, focusing upon removing heat from the flue gas to a point where it can be below the dew point as significant to realizing the total heat recovery for the gas boiler.
TL;DR: In this paper, a computer program has been developed for simulation of the thermal performance of an earth-air heat exchanger for preheating and cooling of supply air, taking account of dynamic variationsof climatic, load and soil conditions.
TL;DR: An exergy analysis model of flat plate collectors is presented, considering non-uniformity in temperature distribution along the absorber plate, and the computation results agree well with experimental data.
Abstract: This study proposes the concept of the local heat loss coefficient and examines the calculation method for the average heat loss coefficient and the average absorber plate temperature. It also presents an exergy analysis model of flat plate collectors, considering non-uniformity in temperature distribution along the absorber plate. The computation results agree well with experimental data. The effects of ambient temperature, solar irradiance, fluid inlet temperature, and fluid mass flow rate on useful heat rate, useful exergy rate, and exergy loss rate are examined. An optimal fluid inlet temperature exists for obtaining the maximum useful exergy rate. The calculated optimal fluid inlet temperature is 69 °C, and the maximum useful exergy rate is 101.6 W. Exergy rate distribution is analyzed when ambient temperature, solar irradiance, fluid mass flow rate, and fluid inlet temperature are set to 20 °C, 800 W/m2, 0.05 kg/s, and 50 °C, respectively. The exergy efficiency is 5.96%, and the largest exergy loss is caused by the temperature difference between the absorber plate surface and the sun, accounting for 72.86% of the total exergy rate.
TL;DR: In this article, the authors proposed a new mathematical relation of working fluid selection for subcritical ORC coupled with the types of low-grade heat sources, and the theoretical formulas of net power output and thermal efficiency were proposed to elucidate the selection criteria of working fluids.
TL;DR: In this article, a two-phase heat exchanger model was developed for temperature and vapor quality prediction and for control design of the waste heat recovery system in heavy-duty diesel engines, where energy is recovered from both exhaust gas recirculation line and the main exhaust line.
TL;DR: In this article, the authors developed a numerical simulation model to predict the ground heat exchange rate (HER) of an energy-foundation system integrated with the horizontal heat exchanger, and the developed model was coupled with ground heat transfer model, ground surface heat model and ground exchanger model, and case studies were conducted at different conditions of design and installation with variables such as pipe spacing, installation depth, pipe diameter, circulation water temperature, flow rate, and operation condition.
TL;DR: In this paper, a comparison of six gaseous and liquid heat transfer fluid (HTF) was carried out to determine their suitability for use in a high temperature thermal storage unit with flat slabs of phase change materials.
TL;DR: In this article, a single slope solar still having a transparent glass cover is considered to be heated at its bottom by a circulating heat transfer fluid, and the rate of this flow and the temperature at the inlet of the still are assumed to be controlled such that they are adjusted to the desired values.
TL;DR: In this article, the authors introduce a new concept utilizing a solid heat transfer medium in the form of spheres for heat recovery from particles, which leads to a high surface area and enables an improved heat transfer.
TL;DR: In this article, an optimization model is developed for plate-fin heat exchangers (PFHEs) based on the entropy generation minimization method, which takes into account the irreversibility due to both irreversible heat transfer and pressure drop.
TL;DR: In this paper, a two-dimensional model is developed to simulate the transient response of a heat pipe-assisted latent heat thermal energy storage (LHTES) unit that is combined with dish-Stirling solar power generation systems.
Abstract: A two-dimensional model is developed to simulate the transient response of a heat pipe-assisted latent heat thermal energy storage (LHTES) unit that is combined with dish-Stirling solar power generation systems. The unit consists of a container which houses a phase change material (PCM) and two sets of interlaced input and output heat pipes (HPs) embedded in the PCM. The LHTES unit is exposed to time-varying concentrated solar irradiance. A three-stage operating scenario is investigated that includes: (i) charging only, (ii) simultaneous charging and discharging, and (iii) discharging only. In general, it was found that the PCM damps the temporal variations of the input solar irradiance, and provides relatively smooth thermal power to the engine over a time period that can extend to after-sunset hours. Heat pipe spacing was identified as a key parameter to control the dynamic response of the unit. The system with the greatest (smallest) heat pipe spacing was found to have the greatest (smallest) temperature drops across the LHTES, as well as the maximum (minimum) amount of PCM melting and solidification. Exergy analyses were also performed, and it was found that the exergy efficiencies of all the systems considered were greater than 97%, with the maximum exergy efficiency associated with the system having the minimum heat pipe spacing.Copyright © 2013 by ASME
TL;DR: It is proved that when the heat engines operate at the maximum power under the tight-coupling condition without heat leakage the work output is just half of the exergy, which is known as the maximum available work extracted from a heat source.
Abstract: We formulate the work output and efficiency for linear irreversible heat engines working between a finite-sized hot heat source and an infinite-sized cold heat reservoir until the total system reaches the final thermal equilibrium state with a uniform temperature. We prove that when the heat engines operate at the maximum power under the tight-coupling condition without heat leakage the work output is just half of the exergy, which is known as the maximum available work extracted from a heat source. As a consequence, the corresponding efficiency is also half of its quasistatic counterpart.
TL;DR: In this article, a 36-tube Stirling engine heater with a piston-link drive machine was used to study heat transfer characteristics of oscillating flows and the influences of the overall heating power, oscillating frequency and gas pressure on the heat transfer properties were investigated.
TL;DR: In this paper, a three-dimensional compressible CFD code has been developed to study the heat transfer characteristics of a twin-power piston γ -type Stirling engine, and the results include temperature contours, velocity vectors, and distributions of local heat flux along solid boundaries at several important time steps.