IFA world premiere: Miele presents solar dryer / Cost- and primary energy savings
Tumble dryers harness sun's power
Gütersloh/Berlin, August 31, 2011. – A solar dryer can help slash energy costs and primary energy consumption. Compared with a heat-pump dryer, costs can be cut by half, or even by up to 80% if conventional vented or condenser dryers are taken as the benchmark. Primary energy efficiencies can also be as high as 80%. This is the result of a study compiled jointly by Miele and the Brunswick-based solar technology manufacturer Solvis. At IFA 2011, Miele and Solvis will be presenting the world's first solar-heated tumble dryer. The market launch is due for autumn of next year.
In the past, it was not possible to use solar energy for tumble drying without first converting the sun's rays into electricity. Such an approach is, though, of great relevance as interest in harnessing solar power in homes is likely to grow over the coming years to represent an increasing share of domestic power.
The solar dryer featuring in the Miele project makes use of on-roof solar-thermal collectors in combination with a Solvis stratified storage tank. The freeze-protected fluid in circulation in the collectors transfers its heat load to the water in the tank. Temperature layering in the tank means that various water temperatures are available for a variety of uses. The solar dryer requires the water with the highest temperature which is also used for tap water.
The solar dryer is connected to the stratified storage tank via four lines: The first pipe feeds hot water into the dryer where its heat is transferred to the process air via a heat exchanger. In the process, the water cools down and is returned to the tank via a second pipe. There, it is heated afresh for re-use. To extract moisture from the hot, damp air in the dryer using the principle of condensation, cold water is fed into the appliance from the tank through a third connection to provide a cold surface on which the air can shed its moisture load. Return feed of the now warm water is via a fourth pipe.
Thanks to this closed circuit, the system is virtually loss-free as for the most part the heat extracted for drying laundry is re-introduced to the storage tank in the condensation process.
In terms of drying results, the solar dryer is on a par with its more conventional counterparts. Thanks to the low temperature of the process air, comparable to that on a heat-pump dryer, the solar dryer is particularly gentle on fabrics.
Solar drying contributes towards increasing the efficiency of solar-thermal collector systems, particularly during sun-rich summer months. Water heating in the stratified storage tank can also easily be combined with other energy sources, in particular renewables such as biomass or geothermal energy. This makes for cost-efficient and resource-saving tumble drying even in winter when less solar power is available. The use of tap water from the storge tank for other domestic appliances such as dishwashers or (AllWater) washing machines is equally viable.
Company profile: Miele is world leader in the production of premium domestic appliances including cooking, baking and steam-cooking appliances, refrigeration products, coffee makers, dishwashers and laundry and floorcare products. This line-up is augmented by dishwashers, washer-extractors and tumble dryers for commercial use as well as washer-disinfectors and sterilisers for use in medical and laboratory applications (Miele Professional). The company, founded in 1899, has 8 production plants in Germany and one plant each in Austria, the Czech Republic, China and Romania. 2010/11 turnover amounted to approx. EUR 2.95 bn with sales outside Germany accounting for 70%. Miele has its own wholly owned sales subsidiaries or operates through distributors in almost 100 countries. The Miele company, now in the fourth generation of family ownership, employs a workforce of over 16,500 with two-thirds in Germany. The company has its headquarters in Gütersloh, Westphalia.
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