Actually, I deal far too little with interesting products for saving energy. Maybe I should do that more often and watch the market better. Many people are looking for specific products or want to know which products are recommended or generally help to further reduce energy consumption.
A product that caught my eye very early on and that I have reported on several times is the solar dryer. This dryer, which was developed by Miele in cooperation with solar thermal systems supplier Solvis, is now ready for series production. Since the device is also shown on Miele’s website, it also appears to be commercially available. The final development details are complete, as is extensive product testing to meet Miele’s quality criteria. At the IFA 2011, Miele and Solvis had already presented the first project study. I have already reported on this several times, most recently in the run-up to ISH 2013 after a report from Solvis.
The “T 8881 S EcoComfort” is connected to the heating system of the house, which in turn is connected to the solar thermal system on the roof. This significantly reduces energy consumption, because the solar dryer with energy efficiency class A +++ is up to 80 percent more economical than exhaust air or condenser dryer and up to 60 percent more economical than an already very energy-efficient heat pump dryer. The solar dryer uses solar energy directly, i.e. without converting it into electricity. The basis for this is a solar thermal system that supplies the heating system with warm water via a layered storage tank.
With normal use in a four-person household, the additional costs of the device (about 500 euros) are amortized within a good seven years. Another advantage is that the solar dryer contributes to the utilization of the solar system in summer. In winter, the water in the stratified storage tank could alternatively be heated using biomass or geothermal energy to save energy.
The solar dryer is connected to the stratified storage tank via four lines. The first feeds warm water into the dryer, which transfers the heat to the dryer air in a heat exchanger. The water cools down and returns to the stratified storage tank via a second line. A third connection brings cooler water from the storage tank into the dryer in order to cool down the warm dryer air again. The humid air is then cooled down in a second heat exchanger and the water is condensed out of the air. This is fed back into the storage layers via a fourth line. Thanks to the closed circuit system between the solar dryer and the storage tank, the system works largely without temperature losses, because the majority of the heat removed for drying is returned to the water in the storage tank in layers in the condensation process.
According to Miele, the drying result of the solar dryer is comparable to that of conventional devices. The low temperature of the process air corresponds to that in the heat pump dryer, so that the textiles are also particularly protected here. Solar-heated water can also be used for other Miele household appliances such as dishwashers and (all-water) washing machines.