Abstract: The present invention relates to a thermal insulator using closed cell expanded perlite. The thermal insulator using closed cell expanded perlite of the present invention includes: expanded perlite 10 to 84 wt %ç, including dried and expanded perlite ore particles, having a surface with a closed cell shape, as an active ingredient; a liquid binder 15 to 85 wt %; and a reinforcing fiber 0.25 to 5 wt %. Accordingly, the present invention provides a thermal insulator, which enhances the rigidity of expanded perlite, minimizes porosity and gaps between the expanded perlite particles, by reducing compression ratio during compression molding, which results in lower density, improves constructability by lowering thermal conductivity, reduces material and energy costs and can reduce the area required for equipment installation by reducing the thickness of the thermal insulator.

Abstract: A method for controlling the temperature of hot water through an operation of a circulation pump according to the present invention includes: judging whether a user uses the hot water; judging whether one of the circulation pump operating modes is selected; and circulating the hot water in an outflow pipe to an inflow pipe by operating the circulation pump provided on a bypass pipe connecting the inflow pipe which direct water enters and the outflow pipe through which heated hot water flows out to each other when the user uses the hot water and selects one of the circulation pump operating modes, thereby controlling a temperature difference of the hot water that flows out from a water heater to be reduced.

Abstract: In a hot water supply system, a heat exchanger transfers heat from a heating device to inflow water to supply the inflow water at a user-set temperature. A flow sensor measures a flow rate of inflow water. A water tank stores outflow water discharged from the heat exchanger. A first temperature sensor, installed on an inlet pipe through which the inflow water flows, measures a temperature of the inflow water. A second temperature sensor, installed on an outlet pipe through which the outflow water flows, measures a temperature of the outflow water discharged from the heat exchanger. A controller includes an input unit to receive input from a user, wherein the controller controls an operation of the heating device based on at least one of: (1) comparison between the user-set temperature and the temperature of the outflow water; (2) variation in the flow rate; or (3) any combination thereof.