Larry Brown's

The Heaviside Plan ™

Hot Water

Introduction

In Space Heat we outlined the development of Free Heat ™ units to heat individual rooms. Now we take up the matter of hot water. Currently hot water for the whole house is heated in a central hot water heater which may be the tank type or tankless type. Pipes convey the hot water from the hot water heater throughout the house. It would be quite easy to simply replace the heat source in the hot water heater with Free Heat ™ units. However, this is not particularly efficient, but as long as the heat comes from burning some kind of fuel, or electric power, it was the only choice. With the advent of Free Heat ™ units another possibility appears--heating the water at the Point of Use (POU). This has the advantage not requiring separate hot water pipes to each fixture and of having hot water available at any time without having to run water until it gets hot.

Development

Sinks and lavatories can have the Free Heat ™ hot water unit installed under the sink or lavatory. For tubs and showers the heating unit could be placed in the adjoining wall. The cold water would be heated by the Free Heat ™ hot water unit when hot water was desired. The Free Heat ™ hot water unit would consist of a Free Heat ™ unit and a heat exchanger to conduct the heat into the flowing water. The Free Heat ™ unit would be sized for the temperature rise needed and the mass flow rate of the water. The British Thermal Unit (BTU) is defined as the heat required to raise one pound of water one fahrenheit degree.

If the cold water is at 32 degrees and 112 degree water is desired with a flow rate of one gallon (approximately 8 pounds) per minute, the heat required is 34,800 BTU per hour ((112 - 32) X 8 X 60). This would require 7 of the 5,000 BTU per hour Free Heat ™ units (or one or more larger units). The water heater would be have a temperature sensor at the output so the water temperature can be thermostatically controlled. If there are multiple units, all the units can be controlled from the same temperature control unit. The temperature control unit would have control(s) so users can select the desired water temperature.

Summary

Individual Free Heat ™ units to heat water at the Point Of Use (POU). Individual POU units at each hot/warm water outlet will eliminate the need for a hot water tank and a hot water pipe to each water fixture. The POU's would be thermostatically controlled so the water would always be at the desired temperature after the first pint of water drawn.

Updated:  May 14, A.D. 2009

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