Energy savings: performance tests of domestic (waste) water heat recovery systems at the CCTR December 2007 study by the Canadian Centre for Residential Technologies.
The recovery of heat domestic water is a relatively simple technology that allows households to reduce their consumption of hot water and prolong the uptime of hot water during periods of high demand or continuous use.
Heat recovery of domestic water taking advantage of the principle of surface tension that water tends to flow along the walls of the vertical drain pipes. This results in a ratio very high "contact / volume surface" that extracts heat domestic water by wrapping the cold water inlet pipe around the vertical drain pipe. There are currently a number of heat recovery Patented domestic waters.
A research program to assess how these devices can recover energy was conducted by the Canadian Centre for Housing Technology (CCHT).
Six heat exchangers series production were tested as part of two studies respectively 2005 and 2006. These devices consisted of a copper drain pipe 3 inch (76,2 mm) nominal diameter and variable length surrounded by a flexible copper pipe 1 / 2 inch (12,7 mm) or 3 / 8 inches ( 9,5 mm) nominal diameter. Cold water flows through the small flexible pipe to capture the heat domestic water, as shown in Figure 1. The provision of driving around the drain pipe, as well as the shape of the various lines, varies from one model to another.
In most homes, there is "events" draining domestic waters occur only cold water (toilet), cold water and hot water (sinks, laundry and shower) or hot water only (dishwasher).
In some cases, the hot water flows simultaneously in supply and drain pipes (sink and shower), while in others there is a delay between the delivery of hot water and the water drain temperate (laundry, dishwasher and bathroom). It important to distinguish between these types of events, because the type of generic heat recovery in question here has a very low storage capacity and is more effective at events where water flows and at the same time time it changes, as is the case showers.