130. Refrigerating Plants. Refrigerating plants are sometimes installed in private dwellings. These consist of a motor and a machine for compressing gas, a chamber which is to be cooled, and sometimes coils of pipe containing brine.
When the gas—for example, ammonia or carbon dioxide—is compressed, it heats the pump which compresses it. That is, when a liquid or gas is being compressed, it gives up heat. When a liquid or gas expands, it takes heat from somewhere. In refrigerating plants, the expanding gas is made to take the heat either directly from the refrigerator or storeroom, or from brine which is then used for cooling the refrigerator or room. Refrigerating plants require the same care as pumps, motors and refrigerators.
Fig. 61-b. Cooling tank.
131. Water Coolers. Since ice is not always pure, it is necessary to use cooling devices which do not permit it to come into direct contact with the water. One type of water cooler consists of a can set in an ice box with a pipe leading to the outside so that the box does not have to be opened every time that water is wanted (Fig. 62). This can should be made so that it may be removed, washed and scalded.
Another cooler consists of a tank or water bottle placed on the outside of a refrigerator or box of ice with a pipe leading thru the refrigerator or box of ice (Fig. 63). The water flowing thru the pipe is cooled. The pipe ends at the outside of the ice box with a faucet to let out the water. This cooler cools only the water flowing into the pipe instead of the entire tank of water.
Fig. 62. Water cooler containing
water tank.
Fig. 63. Sectional view of
water cooler.