Showing papers on "Heat exchanger published in 2010"
TL;DR: In this paper, the heat transfer coefficient and friction factor of the TiO 2 -water nanofluids flowing in a horizontal double tube counter-flow heat exchanger under turbulent flow conditions, experimentally.
623 citations
TL;DR: In this article, a numerical model of an ORC and an experimental study carried out on a prototype working with refrigerant HCFC-123, whose heat sources consist in two hot air flows.
493 citations
Patent•
25 Aug 2010
TL;DR: In this paper, a reversible air compressor-expander uses mechanical power to compress air and converts the energy stored in compressed air to mechanical power when it is acting as an expander.
Abstract: A compressed-air energy storage system according to embodiments of the present invention comprises a reversible mechanism to compress and expand air, one or more compressed air storage tanks, a control system, one or more heat exchangers, and, in certain embodiments of the invention, a motor-generator. The reversible air compressor-expander uses mechanical power to compress air (when it is acting as a compressor) and converts the energy stored in compressed air to mechanical power (when it is acting as an expander). In certain embodiments, the compressor-expander comprises one or more stages, each stage consisting of pressure vessel (the “pressure cell”) partially filled with water or other liquid. In some embodiments, the pressure vessel communicates with one or more cylinder devices to exchange air and liquid with the cylinder chamber(s) thereof. Suitable valving allows air to enter and leave the pressure cell and cylinder device, if present, under electronic control.
413 citations
TL;DR: In this paper, a new 1D and 2D solid cylindrical source model for ground-coupled heat pump (GCHP) systems is presented to consider both the radial dimension and the heat capacity of the borehole or pile.
275 citations
TL;DR: In this paper, a transient and implicit model based on computational fluid dynamics was developed to predict the thermal performance and cooling capacity of earth-air-pipe heat exchanger systems, which was validated against experimental investigations on an experimental set-up in Ajmer (Western India). Good agreement between simulated results and experimental data is obtained.
247 citations
TL;DR: In this article, the authors explored the use of a non-traditional optimization technique; called particle swarm optimization (PSO), for design optimization of shell-and-tube heat exchangers from economic view point.
238 citations
TL;DR: In this article, a set of CFD simulations for a single shell and single tube pass heat exchanger with a variable number of baffles and turbulent flow were performed, and the best turbulence model among the ones considered was determined by comparing the CFD results of heat transfer coefficient, outlet temperature and pressure drop with the Bell-Delaware method results.
237 citations
TL;DR: In this article, the state-of-the-art of ceramic materials for use in a variety of heat transfer systems is reported, and a comprehensive study of the use of these emerging materials in both conventional HVAC&R systems and emerging energy technologies is presented.
233 citations
TL;DR: In this article, the authors used the Fast and elitist non-dominated sorting genetic algorithm (NSGA-II) to obtain the maximum effectiveness and the minimum total annual cost (sum of investment and operation costs) as two objective functions.
233 citations
TL;DR: In this paper, a life cycle impact assessment of ground-source heat pump (GSHP) systems is presented to assess the entire energy flows and resources use for any product or service that is involved in the life cycle of such a technology.
Abstract: Shallow geothermal systems such as open and closed geothermal heat pump (GHP) systems are considered to be an efficient and renewable energy technology for cooling and heating of buildings and other facilities. The numbers of installed ground source heat pump (GSHP) systems, for example, is continuously increasing worldwide. The objective of the current study is not only to discuss the net energy consumption and greenhouse gas (GHG) emissions or savings by GHP operation, but also to fully examine environmental burdens and benefits related to applications of such shallow geothermal systems by employing a state-of the-art life cycle assessment (LCA). The latter enables us to assess the entire energy flows and resources use for any product or service that is involved in the life cycle of such a technology. The applied life cycle impact assessment methodology (ReCiPe 2008) shows the relative contributions of resources depletion (34%), human health (43%) and ecosystem quality (23%) of such GSHP systems to the overall environmental damage. Climate change, as one impact category among 18 others, contributes 55.4% to the total environmental impacts. The life cycle impact assessment also demonstrates that the supplied electricity for the operation of the heat pump is the primary contributor to the environmental impact of GSHP systems, followed by the heat pump refrigerant, production of the heat pump, transport, heat carrier liquid, borehole and borehole heat exchanger (BHE). GHG emissions related to the use of such GSHP systems are carefully reviewed; an average of 63 t CO 2 equivalent emissions is calculated for a life cycle of 20 years using the Continental European electricity mix with 0.599 kg CO 2 eq/kWh. However, resulting CO 2 eq savings for Europe, which are between −31% and 88% in comparison to conventional heating systems such as oil fired boilers and gas furnaces, largely depend on the primary resource of the supplied electricity for the heat pump, the climatic conditions and the inclusion of passive cooling capabilities. Factors such as degradation of coefficient of performance, as well as total leakage of the heat carrier fluid into the soil and aquifer are also carefully assessed, but show only minor environmental impacts.
189 citations
TL;DR: In this paper, an experimental investigation of the performance of thermosyphons charged with water as well as the dielectric heat transfer liquids FC-84, FC-77 and FC-3283 has been carried out.
TL;DR: In this article, the authors examined a novel system that combined a solid oxide fuel cell (SOFC) and an organic Rankine cycle (ORC) for cooling, heating and power production (trigeneration) through exergy analysis.
TL;DR: In this paper, a direct-coupled PV/thermal air collector was designed, built, and tested at a geographic location of Kerman, Iran, where a thin aluminum sheet suspended at the middle of air channel was used to increase the heat exchange surface and consequently improve heat extraction from PV panels.
TL;DR: In this paper, a shell and tube heat exchanger was first thermally modeled using e-NTU method while Bell-Delaware procedure was applied to estimate its shell side heat transfer coefficient and pressure drop.
TL;DR: Two model validation studies on an experimental system show that the complete dynamic model developed in Matlab/Simulink can well predict the system dynamics in shut-down and start-up transients.
Abstract: This paper presents an advanced switched modeling approach for vapor compression cycle (VCC) systems used in Air Conditioning and Refrigeration. Building upon recent work ( McKinley and Alleyne, 2008 ), a complete dynamic VCC model is presented that is able to describe the severe transient behaviors in heat exchangers (condenser/evaporator), while maintaining the moving-boundary framework, under compressor shut-down and start-up operations. The heat exchanger models retain a constant structure, but accommodate different model representations. Novel switching schemes between different representations and pseudo-state variables are introduced to accommodate the transitions of dynamic states in heat exchangers while keeping track of the vapor and liquid refrigerant zones during the stop–start transients. Two model validation studies on an experimental system show that the complete dynamic model developed in Matlab/Simulink can well predict the system dynamics in shut-down and start-up transients.
TL;DR: In this article, an approach based on electrical analogy is presented, for this reason named CaRM (CApacity Resistance Model), which allows to consider the fluid flow pattern along the classical vertical ground heat exchangers as a single U-tube, a double U -tube or coaxial pipes, taking into account also the thermal interference between more boreholes.
TL;DR: In this article, the authors investigated the cooling and ventilation in a solar house through combined solar chimney and underground air channel, and they found that the chimney can be perfectly used to power the underground cooling system during the daytime, without any need to electricity.
TL;DR: In this paper, a novel design is proposed to reduce heat transfer irreversibility between conduction oil and HCFC-123 in the heat exchangers while maintaining the stability of electricity output.
TL;DR: In this article, the performance of a horizontal-coupled slinky ground source heat pump (GSHP) at a UK climate was investigated using experimental measurements and 3D numerical simulations.
TL;DR: In this article, the thermal performance and sizing of a 100kW EFGT plant were analyzed at different cycle pressure ratio (rp = 2−8), turbine inlet temperature (TIT = 1050−1350 K), and the heat exchanger cold end temperature difference (CETD) for different operating conditions.
TL;DR: In this article, the authors explored the use of particle swarm optimization (PSO) algorithm for thermodynamic optimization of a cross flow plate-fin heat exchanger, and the results of optimization using PSO are validated by comparing with those obtained by using GA.
TL;DR: In this article, two desiccant-coated heat exchangers, which are actually fin-tube heat exchanging devices coated with silica gel and polymer materials respectively, are investigated experimentally.
TL;DR: In this article, an analytical model of heat and mass transfer processes in a flue gas condensing heat exchanger system was developed to predict the heat transferred from flue gases to cooling water and the condensation rate of water vapor in the fluegas.
TL;DR: In this paper, a simple procedure by which the entropy generation in simultaneous heat and mass exchange devices can be minimized is described. But the procedure is not suitable for a large number of cooling towers.
TL;DR: In this article, a pyroelectric energy converter was designed and tested on co-polymer 60/40 poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] thin films sandwiched between metallic electrodes.
TL;DR: In this paper, a simple single-pass counter-flow heat exchanger installed horizontally beneath the shower drain is employed as a localized heat recovery measure for preheating cold water going to a water heater.
TL;DR: In this paper, a small-scale experimental magnesium hydride tank was designed and tested to illustrate the feasibility of hydrogen storage in magnesium hydroxide, and a numerical model was developed to have a better understanding of the heat and mass transfers in the tank.
Patent•
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TL;DR: In this article, a heat pump system has a refrigerant circuit and a controller (1a), the controller causes the heat-snurce-side heat exchanger (26a, 26b) to function as an evaporator or as a radiator in accordance with an overall heat load of the usage units.
Abstract: A heat pump system (1) has a refrigerant circuit (20) and a controller (1a), The refrigerant circuit (20) has usage units (5a, 5b) connected to a heat source unit (2), the usage units (5a, 5b) having first usage-side heat exchangers (51a, 51b), and the heat source unit (2) having a heat-source-side heat exchanger (26a, 26b) and a compressor (21). The usage units (5a, 5b) further have second usage-side heat exchangers (151a, 151b). The controller (1a) causes the heat-snurce-side heat exchanger (26a, 26b) to function as an evaporator or as a radiator in accordance with an overall heat load of the usage units (5a, 5b) in a state in which the heating operation for heating the aqueous medium by heat radiation of the refrigerant in the first usage-side heat exchangers (51a, slob) or the cooling operation for cooling the aqueous medium by evaporation of the refrigerant in the second usage-side heat exchangers (151a, 151b) has been set for each of the usage units (5a, 5b).
TL;DR: In this article, the main thermal hydraulic challenges in sodium cooled fast reactors, on the basis of the past experience, are summarized and compared using numerical and experimental tools used in the French Atomic Energy Commission (CEA).
Patent•
10 Aug 2010TL;DR: In this paper, the authors presented an exhaust heat recovery device which is configured to perform integral heat exchange between the exhaust gas, the coolant, and the oil during the initial start-up of an engine.
Abstract: The present invention provides an exhaust heat recovery device configured to perform heat exchange between three media such as, exhaust gas, coolant, and oil According to preferred embodiments of the present invention, the exhaust heat recovery device is configured such that the heat of exhaust gas discharged from an engine is transmitted to the coolant and the oil at the same time and direct heat exchange between the coolant and the oil is made, thereby simultaneously increasing the temperature of the coolant and the oil during the initial start-up of the engine (fast warm-up) As a result, it is possible to reduce friction loss of powertrain, thereby improving fuel efficiency Accordingly, an object of the present invention is to provide an exhaust heat recovery device which is configured to perform the integral heat exchange between the exhaust gas, the coolant, and the oil