Non-invasive Demand Response Hot Water Recirculation Pump Signaling and Control Appliance

Abstract

This invention provides demand activation of a hot water recirculation pump to reduce energy wasted from running the pump when its use is not needed. The invention uses momentary water flow at the remote tap as the signaling mechanism. Heated water flowing into the hot water egress pipe raises the temperature of the pipe. A temperature sensor continuously measures the temperature and provides the measurements to a controller where the time rate of change of temperature measurements are detected and used as the signal to operate the recirculation pump. Controller logic processes the digitized output of the temperature sensor, threshold detects the time rate of temperature change, and activates power to the external recirculation pump for timed intervals. This invention requires no modification to existing plumbing in a domestic plumbing system already equipped with a recirculation pump.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001]Not ApplicableFEDERALLY SPONSORED RESEARCH [0002]Not ApplicableBACKGROUND[0003]1. Field[0004]This application relates to hot water recirculation pump controls in domestic plumbing systems.[0005]2. Prior Art[0006]A domestic recirculating hot water system consists of a water heater, supply piping to deliver heated water to water taps in a building, return piping to return water from the taps to the water heater and an electric pump to circulate water flow from the water heater to the taps and then return the water back to the water heater. Circulating the water moves heated water close to each tap in the system such that; on opening the tap, very little water passes through the tap before heated water reaches the tap. The system provides two major benefits; convenience to the user and reduction of water wastage. Convenience results from a reduction in time required for heated water to reach a tap when it is opened. The shortened period of ...

AI Technical Summary

Problems solved by technology

Convenience results from a reduction in time required for heated water to reach a tap when it is opened.

There are energy costs from running the recirculation pump and from heat lost from the heated water in the supply and return piping.

In addition, temporary changes in the user's schedule are not always accommodated by the timer and when the user requires hot water outside of the timer's active period, the user must wait for heated water to flow from the hot water heater to the tap while the unused cold water is discarded.2. Flow detection.

The wiring would be difficult and costly to add to a facility with pre-existing walls.4. Pressure sensor.

There are several problems with this concept; electrical circuits are frequently not organized in areas isolated to hot water usage areas, frequently humans in areas with hot water taps do not energize lighting before using hot water, many times humans do energize lighting and do not intend to use hot water.

In addition to these functional limitations, the system requires modification to the electrical circuits to install sensors that indicate usage of the circuits.

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