Showing papers on "Thermal reservoir published in 1985"

Quantum theory of a free particle interacting with a linearly dissipative environment.

Abstract: The quantum-mechanical motion of a free particle coupled to a linearly dissipative environment is analyzed in the Hamiltonian formalism. The total Hamiltonian is diagonalized and its eigenstates displayed. These results are used to discuss the role of initial conditions on the subsequent motion. A widely used initial condition---heat bath uncoupled from particle---is compared with another one in which the initial off-diagonal coherence of the reduced density matrix is comparable to that in the state of thermal equilibrium of the coupled system. Different transient behaviors, on time scales longer than the inverse cutoff frequency of the bath are found. The mean-square momentum of the particle in the steady state is found to depend on this highest bath frequency. An analysis of the correlated states of particle and heat reservoir shows that the latter behaves in some sense like a position-measuring apparatus.

Exact results for a damped quantum-mechanical harmonic oscillator

Abstract: Exact calculations for a quantum oscillator linearly coupled to a thermal reservoir are presented. Explicit results (variances and correlations) for the response and the spontaneous fluctuations are evaluated for two different models of the heat bath; a reservoir with a spectrum which is similar to that of acoustic phonons and another which is analogous to optic phonons. The low-temperature behavior is shown to depend sensitively on the spectral density of the thermal reservoir. The mass and the frequency of the oscillator become renormalized through the coupling to the bath. These renormalizations are intrinsically frequency dependent. Moreover, the commonly used form of Ehrenfest's equation for the dynamics of the linearly damped oscillator is shown to only be a reasonable approximation within certain frequency regimes.

Twin reservoir heat transfer circuit

Abstract: A refrigeration or air-conditioner circuit has an ejector through which refrigerant is driven from a heated supply reservoir to an unheated collecting reservoir. The ejector sucks refrigerant from a branch circuit containing an expansion valve and an evaporative heat-exchanger providing cooling. Valving interchanges the functions of the two reservoirs when the refrigerant supply reservoir is empty so that operation of the circuit is uninterrupted.

Additionally heating device for water in bathtub

Abstract: PURPOSE:To provide a heat value required to additionally heat the water in the bathtub in a short period of time by making up a heat accumulating tank with a heat accumulating material to accumulate the heat generated by an electric heater and a heat insulating material surrounding the same, and transmitting the heat stored in the heat accumulating material through a heat pipe to the water in the bathtub. CONSTITUTION:The heat accumulating tank 2 comporises a heat accumulating material 4 to accumulate the heat released from an electric heater 3 and a heat insulating material 5 surrounding the heat accumulating material 4. A heat pipe 6 which has a heat collecting part 6b on the side of the heat accumulating material 4 transmits the heat accumulated in the heat accumulating material 4 to the water in the bathtub 1 through the heat releasing part 6b. The heat pipe 6 has on its way a valve 7. By this arrangement, a heat value required to additionally heat the water in the bathtub can be provided in a short period of time without requiring much power consumption.

Variable Conductance Heat Pipes: A First-Order Model

Abstract: The variable-conductance heat pipe (VCHP) is modeled as a one-dimensional fin with a discrete heated zone between unknown axial locations /t and -/0. The length /t is constrained by the distribution of noncondensable gas throughout the length of the pipe and in a temperature-controlled, wicked reservoir; the length -/0 must be determined empirically. Internal heat and mass transfer processes are subsumed by postulating that condensation imposes a specified local heat flux in the heated zone only. An analytically tractable heat flux distribution is assumed by introducing a parameter s that must be determined either empirically or intuitively. The heat pipe operates in a steady state and loses energy either by convection or linearized radiation, with different values of heat loss coefficient in the active and inactive condenser zones. A closed-form solution for axial temperature is found in terms of heat load, reservoir temperature, environmental conditions, wick/wall thermal conductance, the two parameters ( —/0,s), and the condensation front location lv An algebraic expression for the condensation front is obtained from the noncondensable gas inventory; the mass distribution integral is decomposed into zonal integrals and each integral is evaluated by a mean value approximation based on mean zonal temperature. The temperature and condensation front equations must be solved simultaneously to predict VCHP performance. Data of Edwards and Marcus are used to evaluate the empirical constants (-/0,s). An example is included to illustrate how the formulation may be used to predict diffusion freezeout and specify the gas reservoir volume.

Engineering evaluation of geothermal reservoirs

Abstract: Reservoir engineering evaluation of geothermal systems attempts to provide answers on the extent of the reserves, their probable longevity and the deliverability and production rate of the reservoir. Economic decisions on the desirability of the exploitation of the particular reservoir hinge on these findings. This paper presents a set of calculational procedure and thinking sequences available to the geothermal reservoir engineer that would aid in an appropriate management decision. An exploitable geothermal system consists of a fluid as well as a heat reservoir. Since much of the heat is stored in the confining rock, reinjection strategies are outlines for the efficient mining of heat.

On the phase-change thermal energy storage/heat pump system.

Abstract: A high-performance latent heat thermal energy storage (TES) / heat pump system was proposed. The transient thermal characteristics of the latent heat TES / heat pump system were experimentally revealed in detail. And it is shown that the proposed system has high coefficient of performances of 4.2∼5.0 ( Space heating mode). A simulation of the spherical capsule bed for melting process was also done under the assumption that heat conduction is dominant mode. The comparison between simulation results and experiment has shown that the agreement between the two is excellent. The present system eliminates so-called supercooling problem which is especially important for inorganic hydrates, and it also extends the possibility to select change materials.

Seal mechanism of rotary regenerative type heat exchanger

Abstract: PURPOSE:To improve the reliability of a seal mechanism by a method wherein a gas between the tip of a seal and a fan plate from the axis-of-rotation side towards the outer peripheral side of a rotary heat reservoir is kept nearly constant regardless of the thermal expansion of the rotary heat reservoir. CONSTITUTION:Buffering gears 18a and 18b are respectively fitted to fan plates 5a and 5b. Roller bearings 21a and 21b respectively support the rotating shafts 7a and 7b of guide rollers 6a and 6b, to which rotor tyres 14a and 14b are fitted respectively. Due to the structure as just mentioned above, the gaps between the respective tips of seals 10a and 10b and the respective fan plates 5a and 5b can be automatically kept surely constant over a long period of time in a high temperature and highly corrosive fluid with high dust and high moisture contents regardless of the deformation due to the thermal expansion. Accordingly, the reliability of a seal mechanism is improved.

Continuously adjustable heat-pump heating installation with continuously working operating systems

Abstract: An economical heat-pump heating installation is presented, which can be operated continuously in the partial-load range between 0 and 100%. It consists of a continuously working heat pump driven by an internal combustion engine or an electric motor, a small heat reservoir and one or two peak-load boilers which work in modulating fashion. The continuous heat-pump operation is achieved by an improved refrigerant compressor which contains, in addition to its continuously working volume-controlling device, a device for adapting the compression ratio to the saturation pressures, reduced in the partial-load range, in the refrigerant condenser. In addition, the heat pump works with an improved thermodynamic cyclic process, since it utilises extended condensate undercooling to heat the domestic water.