Showing papers on "Micro heat exchanger published in 1978"

A Correlation for Laminar Hydrodynamic Entry Length Solutions for Circular and Noncircular Ducts

Abstract: Laminar hydrodynamic entry length solutions for circular and noncircular ducts are essential in proper design of compact heat exchangers and other heat transfer and fluid flow devices. A closed form equation has been proposed to present these solutions for the circular tube, parallel plates, rectangular, equilateral triangular, and concentric annular ducts. The necessary constants are evaluated and it is shown that the proposed correlation predicts the apparent friction factors within ± 2.4 percent.

Heat pipe bag system

Abstract: Method and apparatus for utilizing the earth as a heat source and heat sink for heating and cooling buildings are disclosed. Flexible material such as hollow plastic or metal foil bags which can be buried in deep, narrow trenches are draped over and clamped to heat transfer fluid conduits or conventional heat pipes vastly increasing the heat transfer surface area serving the conduits or heat pipes. The heat pipe bags contain a heat transfer fluid and can contain wicks which are in heat transfer communication with the heat transfer fluid conduits or other heat pipes. The plastic or metal of the heat pipe bag similarly enclosed the wick forming a closed, sealed system which can also include the conduit or heat pipe. Such conduit-heat pipe bag combination can be used in combination with conventional heat pumps to both heat and cool buildings.

Heat pump heating and cooling system

Abstract: Systems for transferring energy between a conditioned zone, a heat source or sink liquid, and an ambient zone including combination liquid-source, air-source heat pumps with multi-fluid reversing means and an easily manufactured multi-fluid heat exchanger. Specifically three types of heat pumps: a split system of unitary type with conventional refrigerant reversing means, multi-fluid heat exchanger(s), and heat source or sink fluid reversing means; a self-contained or packaged type with conventional refrigerant reversing means, a multi-fluid heat exchanger, a conventional liquid-to-refrigerant heat exchanger, heat source or sink liquid reversing means, and innovative component arrangement which allows ambient air to be utilized as a heat source or sink fluid; a self-contained or packaged type with innovative component arrangement which allows air reversing means, multi-fluid heat exchangers, and heat source or sink liquid reversing means.

Thermal storage reservoirs

Abstract: A thermal storage system for use with a solar collector and/or heat pump includes a plurality of discrete heat reservoirs having regular geometric shapes such as spheres or cylinders for forming a self-sorting array of the reservoirs when stacked in a storage bin. Each reservoir has a shell formed of heat conductive material defining an interior cavity that contains a material of high specific heat for storing heat in the reservoir. A preferred material for economy for reservoir shells in spherelike shapes is plastic with heat conductivity enhancers such as glass or metal particles incorporated into the plastic.

Heat transfer characteristics of heat pipes

Abstract: The heat pipe, an excellent heat transfer device, is expected to become one of the most important devices in heat transfer technologies in the near future. The application of the heat pipe to waste heat recovery equipment (gas-to-gas heat exhangers) was studied. To obtain low-cost, yet high performance heat pipes for this purpose, experiments on several brands of heat pipes available in the Japanese market and also on prototype heat pipes were carried out. It was concluded that the prototype heat pipes satisfied both requirements, low cost and high performance.

Absorption solar powered air conditioning system with storage capacity

Abstract: This air conditioning system includes low pressure water vaporization, transfer and absorption, both in a solution concentrating section using solar radiation or other heat input and in a solution diluting section where heat exchange with ambient fan blown air subsequently permits cooling or heating enclosure air. The fan blown enclosure air is cooled or heated in passing through the same heat exchanger by changing the flow paths of the solutions passing to and from the two unique vapor exchangers, which are described in detail. The solutions are separated but contained in a sealed system with storage volume to give a large heat capacity potential by changing the solution concentration to either cool or heat the enclosure air. The various system operational modes are described in detail, with the functioning of the vapor exchangers and heat exchangers in concert with the flows through pipes and ducts as generated by pumps and fans together with control by valves.

Coolant flow control apparatus for rotating heat exchangers with supercritical fluids

Abstract: The disclosed invention relates to coolant flow control apparatus for rotating heat exchangers such as used with a liquid cooled turbine blade and disc. By employing a combination of inlet and outlet orifices in the constrained coolant path of the apparatus, the liquid coolant can be made to rapidly reach and maintain supercritical temperature and pressure in the heat exchanger over a range of coolant heat absorption rates.

Method and device for defrosting heat exchanger without impairment of its heat exchange efficiency

Abstract: Method and device for defrosting or deicing heat exchangers of the type in which a stream of warm, moist gas, such as warm, used ventilating air--so-called exhaust air--exchanges heat with a cooler medium, such as incoming fresh air, in a contact apparatus, and in which the two media flow through a large number of parallel layers separated from each other by thin walls.

Linear and Non-linear Stability of Heat Exchangers

Abstract: The hydrodynamical problem of one-dimensional flow with a uniform heat input resulting in a change of phase is considered. Equations of mass, momentum, energy and state representing the dynamic behaviour of such a system are reduced to two coupled equations for the density p{x, t) and the inlet velocity 1/(0 on the assumption that the pressure drop applied between the inlet and the outlet is "small". A linear stability analysis is carried out which leads to the problem of computing the zeros of a complicated analytic function. A non-linear analysis is applied to the case of weak instability to find the evolution of the slowly varying amplitude of a small oscillation: in certain circumstances, a "burst" occurs, and in such cases no such small oscillation can exist.

Liquid-fluidized-bed heat exchanger design parameters

Abstract: Liquid-fluidized-bed heat exchangers prevent scale accumulation on heat transfer surfaces and reduce the required heat transfer surface when scaling fluids, such as geothermal water, are used as the primary or working fluid. Liquid-fluidized-bed heat exchangers, principles of operation, and design parameters are described. Horizontal and vertical assemblies are discussed, including problems encountered with both designs. Bed-side heat transfer coefficients are given for limited cases, and a correlation is provided for calculating heat transfer coefficients for horizontal assemblies. A design example for a 60 kW/sub (e)/ (60 kW/sub (electric)/ preheater is included.

Heat exchanging apparatus and method

Abstract: A heat exchanging apparatus for reducing the temperature of a heating fluid prior to thermal communication with a heated fluid. The apparatus includes an integral pre-cooling heat exchanger located within a main heat exchanger. The pre-cooling heat exchanger brings the heating fluid into thermal communication with the heating fluid circulating in the main heat exchanger so that the heated fluid is prevented from departing from nucleate boiling in the main heat exchanger.