Increasing the solar gain by heat-fed and hot water-fed clothes washer and washing machines

Document identifier:
Keyword: Heat-fed machines, Hot-water-fed machines, Solar gain, Electricity saving, Dishwasher, Clothes washer, Washing machine
Publication year: 2006
Relevant Sustainable Development Goals (SDGs):
SDG 7 Affordable and clean energy
The SDG label(s) above have been assigned by


70 to 90% of the electric energy used by dishwashers and washing machines heats the water, the crockery, the laundry and the machine and could just as well be replaced by heating energy from solar collectors, district heating or a boiler. A dishwasher and a washing machine equipped with a heat exchanger and heated by a hot water circulation circuit instead of electricity (heat-fed machines) have been simulated together with solar heating systems for single-family houses in two different climates (Stockholm, Sweden and Miami, USA). The increased heat load will increase the solar gain and this will compensate for the increased energy demand by heat-fed machines due to increased pipe losses and increased electricity used by pumps. Using ordinary machines connected to the hot water pipe (hot water-fed machines) and using only cold water for the rinses in the washing machine gives almost the same solar contribution; however considerably lower electrical energy savings are achieved since extra electricity is needed to heat up the machines to the required washing temperature.


Tomas Persson

Högskolan Dalarna; Miljöteknik
Other publications >>

Mats Rönnelid

Högskolan Dalarna; Miljöteknik
Other publications >>

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