Observing the world of renewable energy and sustainable living

Solar Freezer


A Dutch startup run by brothers Roderick and Floris Wolters has presented an innovative way to utilize the crawl space beneath a dwelling for energy storage purposes. By placing a huge rubber ‘water sack’ (reservoir, like a waterbed), the thermal storage volume is hugely increased compared to conventional water storage in tanks or boilers, allowing for much enhanced buffer periods. Additionally the {solar collector-reservoir-heat pump} system is designed to allow ice formation within the reservoir, making use of the physical property of water that phase change water-ice has as much heat capacity as heating water from 0-80 degree Celcius. The sack is flexible, allowing for maximum available space utilization. Payback times of 6-7 years is claimed.


Editor: the idea to use the otherwise useless crawl space for energy storage is indeed new (to us). It looks like an interesting way of combining heat from solar collectors and heat pump. The buffer seems large enough to cover at least many days, but obviously not an entire winter season. The claim that heating with natural gas becomes superfluous is of course a little deceptive, because it does not mention the energy source needed to operate the heat pump. Additionally, heat pumps are still very expensive on a per household level. Advantages kick in when a single larger heat pump is shared with several households. But nevertheless, the idea is interesting. Not need to dig a huge hole in the garden, no need for permits. On top of that, a hear pump can work on electricity from solar panels, bringing true energy independence within reach.

More Dutch language comments:
[] – Wonen zonder gasrekening met de Solar Freezer
[] – Solar Freezer, schaafijs doet gasrekening verdwijnen?


[] – The idea to use water-ice phase change for thermal energy storage is not new.
[] – Huis warm, gasrekening nul met nieuwe Solar Freezer (update)
[] – SolarFreezer


Single Post Navigation

Comments are closed.

%d bloggers like this: