In a series of e-mails explaining our options, he recommended that our house be cooled in the summer months using our ground source heat pump integrated with our under floor heating system and a ventilation unit with an adapted refrigeration system. He described this approach as innovative which clinched it for us, as we were on a quest for a one-of-a-kind green home.
That decision was made in the middle of winter. Now at the end of June 2014, you may be wondering: how is that working out?
For one thing, the integrated system is a complicated one. Here is another shot of our Plant Room:
From right to left, this photo includes our Bosch geothermal heat pump, our very high tech hot water tank (hot water and buffer), our stacked ventilation systems and the under floor heating system. This photo shows the modification of our heat pump outflow to accommodate the diversion of refrigerant for under floor cooling:
At some point before the hand-off, the key pumps and valves in this system were to have been labeled We recently found these labels and are going to coordinate with redblue energy on their proper location:
The diversion of refrigerant is accomplished by one of two high efficiency circulators from Wilo USA (http://www.wilo-usa.com/wilo-usa-llc-home/wilo-usa/); here is a close up image:
Their website includes information on the pressure and temperature readings that activate the circulation:
Via a series of high tech valves, one circulator diverts refrigerant from the geothermal loop pump modules which are manufactured by Geo-Flo (http://geo-flo.com/)
One significant practical limitation of this approach is the fact that the refrigerant temperature from the geothermal wells is actually too cool to be diverted directly to the under floor heating pipes because of condensation. It actually requires some type of heat exchange which remains a mystery for us. This will be investigated and explained in a future post.
The second major component of our cooling is our Zehnder ComfoCool 350 (http://www.zehnder.co.uk/comfosystems/):
This is a combination of a heat exchanger and dehumidifier. It also has significant limitations in terms of the heat exchange, but is highly efficient in terms of maintaining continuously low levels of humidity in the house (around 40%). We monitor all of our in-home settings with our new Dell Venue tablet (http://www.dell.com/us/p/dell-venue-8-pro/):
This is a compromise we use to access our home automation software (Domovea Client) via Windows because to date there is no Android or iPad app for Domovea available in the US.
It turns out that the house has actually felt comfortable in spite of interior temperatures as high as 80F and outdoor temperatures as high as 95F. We are still experimenting with the ComfoCool and under floor heating settings and have been communicating with redblue energy to learn how to keep the house as cool as possible this summer.
Learning about the energy systems has created a steep learning curve for me. We never had a comprehensive software analysis of the cooling system done before the house was built (although redblue energy did one for an even higher tech green(r)evolution Huf Haus in Cologne, Germany with more information in German language at http://www.huf-haus.com/de/home). This is what that Plant Room looks like:
From my relatively energy-naïve viewpoint, it's really all about our amazing shutters, with more to come about them in a subsequent post.
Earlier this month, we decided to put minimize our carbon footprint even further and bought a Chevrolet 2014 Volt (http://www.chevrolet.com/volt-electric-car):
and a Leviton (http://www.leviton.com) fast charger:
We decided to go with the Volt after looking into other alternatives because of our long driving distance to the Huf Haus (111 miles). We are averaging approximately 80 mpg. We have a Volt-compatible bike rack on order so we can continue to explore the C & O Canal trail and the Western Maryland Rail Trail which are accessible approximately 16 and 24 miles from the house (all on battery with the latter at full range). This is me at Fifteen Mile Creek Aqueduct this weekend
where along the well shaded cool trail all I needed to do was look out for Eastern box turtles
