Chapter 3 - An energy surplus home

More details about our energy surplus home:

Our original energy plan in our house quotation in February 2011 included both a passive solar system (12 high output solar panels) and a photovoltaic system estimated to produce 5.58 kWh and a ventilation system with heat recovery. 

By the time of my 2nd trip to Hartenfels for the formal fit-out, we had elected to have a geothermal heat pump installed for under floor heating and cooling (as opposed to an air source heat pump).  This required an upgrade in our PV system.  redblue energy eventually recommended installation of a Bosch/Aleo PV system with a total load of 11.25 kWp. 





 

Torsten Schneider (redblue energy) chose Morrison Inc. (http://morrisongeothermal.com/index.html ) as our geothermal contractors.  They have 30 years of experience in turn-key geothermal systems in central Pennsylvania and did of the design, drilling, excavation and installation for our 3 ton system.

 

 

 

 

As naïve as we were at the outset, we didn't fully realize that the basic components of a Huf Haus (included in the original quotation) don't typically include any mechanism for cooling the home. 

In fact, the topic of cooling the house didn't come to the forefront until the Huf Haus team came to visit our site in January 2012.

During that visit, Steve casually asked Torsten Schneider (redblue energy) how the geothermal system worked to cool the house.  That led to a very technical response that left us confused and worried about having gotten that far without clarification on cooling.

What followed was a series of e-mails educating us about passive cooling and active cooling.  We leaned that use of our ground source heat pump for passive cooling would require installation of additional mechanical and electrical equipment (including an additional plate exchanger between the source outside and the heating system).  redblue energy also did an extensive analysis of installation of an active cooling system and concluded that the installation and running costs would be significantly greater. We queried him on the use of "inverter technology" to reduce inefficiency but he didn't recommend application of that technology in our project.  He also calculated that active cooling with our geothermal system would require approximately 30% more space in our plant room. And we would no longer have an energy surplus home. That was a deal breaker.

He ended up recommending passive cooling via our under floor system and addition of an adapted refrigeration system on top as an "innovative, easy-to-manage, energy efficient and space saving concept."

Here is the new Plant Room: 

To be honest, we are still worried about whether the house will be comfortably cool in the summer months or whether we will need to flee back to our apartment in Maryland when the weather is blistering hot. Apparently with our system, an interior temperature of 80 degrees Fahrenheit can be achieved when the outside temperature is 90 degrees.  redblue energy wasn't able to do a temperature simulation analysis for the cooling (like they were able to do with heating) because of the complexity and requirement for specialized software, but they did perform a simulation for their Plus Energie show house in Cologne, Germany (green(r)evolution Plus Energie hausl), 

We got another big surprise during our initial site visit which I will describe in my next post . . .