| 摘要 |
A process for reversibly transferring heat between a plurality of zones maintained at different temperature levels, and a heat transfer system useful therein. The technique involves maintaining a solution of a volatile material, e.g., a solution of a non-volatile inorganic salt in ammonia, in a solution tank, feeding the solution into an evaporator to evaporate the ammonia (or other volatile material), and feeding the ammonia vapor thus formed into a separate receiver which is in heat exchange relationship with a low temperature thermal sink, while recycling the solution having a decreased ammonia content to the solution tank. Heat is thus transferred to a low temperature thermal sink, and the procedure is continued to store any desired quantity of thermal energy therein. When it is desired to withdraw heat from the system, the salt/ammonia solution, containing a decreased concentration of the ammonia, is fed into a condenser wherein ammonia vapor is absorbed and additional vapor is introduced by vaporization of ammonia in the receiver, thereby transferring heat from the low temperature thermal sink to the useful temperature level of the condenser. Thermal energy, which may be provided by solar insolation or other low grade heat sources, is thus transferred from the evaporator, stored in a low temperature thermal sink, and recovered from the condenser at useful temperatures. Use of a separate solution tank and receiver facilitates independent control of the instantaneous heat input and output in the evaporator and condenser, and the total thermal storage capacity in the receiver and thermal sink. Use of a working fluid incorporating a first, volatile material such as ammonia, and a second, relatively non-volatile material compatible therewith (such as sodium thiocyanate or other non-volatile inorganic salt) facilitates prolonged, efficient operation of the sequential thermal charging and discharge operations.
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