Abstract: A system for conditioning the air in an enclosure, such as a greenhouse, uses low grade heat contained in a liquid, e.g., condenser cooling water that is normally discharged downstream of a power plant. The system includes an indirect contact heat exchanger with a heat exchange surface having one side contacted by the fluid, and a direct contact air-brine heat exchanger associated with the enclosure including a blower for exchanging air between the enclosure and the air-brine heat exchanger. The system also includes a pump for exchanging brine between the direct contact heat exchanger and the other side of the heat exchange surface of said indirect contact heat exchanger. Thus, an efficient indirect, liquid-to-liquid heat exchange operation takes place between the brine and the low grade heated liquid; and an efficient direct, air-brine heat exchange operation takes place to heat the air in the enclosure without increasing its humidity.

Abstract: A power plant includes a source of water, a heat exchanger having an evaporator side maintained below atmospheric pressure for converting the water to steam, and a turbine responsive to said steam for producing work and heat depleted steam. The heat exchanger also has a condenser side for receiving and condensing the heat depleted steam. The evaporator side of the heat exchanger is separated by a barrier from the condenser side. Concentrated brine from a source thereof is caused to fall in a film on the condenser side of the barrier, and water from the water source is caused to fall in a film on the evaporator side of the barrier. The heat of dilution of the film of concentrated brine, as it is directly contacted by the heat depleted steam in the condenser side of the heat exchanger, is transferred through the barrier from the condenser side to the evaporator side raising the temperature of the film of water on the evaporator side which evaporates in the reduced pressure in the evaporator.

Abstract: A heat exchanger comprises a housing containing upper and lower layers of fluid, the upper layer being less dense than the lower layer. The large and sharp density gradient at the interface between the upper and lower layer acts to prevent mixing of the two layers. A plurality of vertically oriented tubular sleeves that are closed at each end and filled with fresh water are located in the housing such that the axial ends of each tubular sleeve are in different ones of the layers. Heat added to the liquid in the lower layer is transferred to the liquid in the upper layer through the medium of the water container in the tubular sleeves.