Abstract: In this invention, a cooling tower pack comprises a plurality of pack elements, each of which in plan has a stepped corrugate shape with a series of bridge portions separated by webs, each element in side elevation having a curved corrugate shape, and each element having small lands which are abutted by adjacent elements and thereby separate the elements and avoid large face-to-face contiguity areas, the lands causing only a minimum of crevice area between the adjacent elements of the pack.

Abstract: An air conditioner wherein supply air is first passed through the supply air passages of an air-to-air heat exchanger, then over a first refrigerant-to-air heat exchanger, into the space to be air conditioned, and return air from that space is passed throught the air-to-air heat exchanger, through a second refrigerant-to-air heat exchanger, and discharged to atmosphere, the refrigerant heat exchangers being the condenser and evaporator of a closed refrigeration system driven by a heat pump compressor.

Abstract: A heat exchanger having a number of sheets retained in spaced relationship with one another by projections outstanding from the sheet surfaces. Some at least of the sheets are provided with return flanges and the arrangement is such that return flanges of a sheet lie contiguous with an adjacent sheet so as to define therewith a fluid flow passage. The flanges of the next adjacent sheet are angled with respect to those of the first to define a second passage which extends in a different direction. Two sets of passages are formed thereby and the sheets constitute heat transfer means between adjacent passages. Each set of passages forms a fluid flow conduit. The pack is formed without cementing or welding the sheets together.