Chapter 13 - Underfloor cooling 101

For the past two months since my last post, Steve has been trouble-shooting an important component of our home energy plan - underfloor cooling.  This was a component that hadn't been tested during our handoff which occurred during a cool month of the year.

Our plant room contained all the necessary components for the required warming of the brine from the geothermal pump:

But it was clear there was something wrong in terms of the relay between the pump and the heat exchanger responsible for warming the brine to the lowest temperature which would avert condensation under the floor.

Steve was able to provide some detailed data demonstrating the problem which was relayed back to redblue Energy (http://www.redblue-energy.com/home) who then communicated with our local electrician from MEC:



The system is managed using the Exigo platform (http://www.exigo.com/services/) from Regin (http://www.regincontrols.com/en-GB/home/) which is an international company specializing in indoor comfort solutions.

With a lot of communication and cooperation between Matt Radaker from MEC (http://mec-electrical.com/) and Stefan from redblue Energy in Muschenbach Germany via teleconference, the troublesome relay switches were identified and corrected and some valves were adjusted and now we have seamless switching from underfloor heating and cooling.  It's working!  And, we can monitor it remotely using an IP address on our home intranet.  For example, right now, the system looks like this:

Looking a little closer, this is the current status of our heat pump and heat circuit:



This may not reproduce well, but we also obtained the schematic of our entire home energy plan:



which I am including to demonstrate the incredible expertise of and support from redblue Energy. 

We are thrilled to have all of the energy systems in working order and have enjoyed our very comfortably cool and low humidity home through the end of summer.  The system won't be really challenged again until next summer.

We have had two major disappointments over the past two months.  The first is, that in spite of herculean efforts on the part of our financial manager at Morgan Stanley 

(http://www.morganstanley.com/), we were unable to secure any type of home equity loan on our home. We went through multiple failed attempts to get it appraised all of which were denied because there are no comparables.  We wanted a one-of-kind home and now we have one which precludes any type of appraisal which is mandatory for a loan. The other disappointment relates to a flat out rejection by Dwell magazine (http://www.dwell.com/magazine)

for my project submission.  One of the editors told me that this house is definitely not what they are looking for in their publication.  This is ironic because the magazine has literally been the mental inspiration of this project since its outset.  The Dwell website recently featured the Honda Smart Home US (http://www.hondasmarthome.com/tagged/heatingandcooling)

which has many features similar to ours and makes us envious about photovoltaic battery storage, which we may pursue at some point when we live in Bedford PA full time.

The Dwell editorial staff may not love our home, but we certainly do.



Chapter 12 - Keeping cool

Looking back, one of the most memorable days of our green home building journey occurred during our Site Visit on January 29, 2012.  That was the day Torsten Schneider, technical manager of redblue energy, our home technology firm, advised us to have our home engineered with passive cooling as opposed to active cooling, otherwise known as the ubiquitous type of air conditioning found in most US homes.

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

 

 

 





Chapter 11 - Home sweet complicated home

For the past two months, Steve and I have spent most of our weekends in our new home:

We have been tracking our West Penn net meter which tracks the kWh we are transferring to the grid and what we are utilizing from the grid.  Here is a graph of our current energy surplus: 

 

 

We have had some home furnishings delivered from Room & Board.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

We also had to make our first service call to Morrison Geothermal. 

Several weeks ago, Steve noticed some minor leakage of the bluish tinged refrigerant from our TW series water-to-water (ground source) Bosch heat pump (http://www.bosch-climate.us/products-bosch-thermotechnology/geothermal-heat-pumps/). The technician was able to identify a leak in the one of the load side connections and promptly repaired it. 

We have also had some consternation when our Domovea server indicated that the ground source heat pump had switched to cooling mode (possibly during one unexpectedly warm day) even though the pump was still heating the house via the in-floor heating.  However, after our pump was repaired, it was clear that the pump was heating the tank that is responsible for the in-floor heating but the actuators were not opening to allow heating of the floors.  This is the upstairs unit containing the actuators and valves:

 

 

 

It got pretty chilly.  Steve contacted redblue Energy and sent some screen shots of our cooling-heating set point configuration for all of our rooms except the bathrooms. He also did some trouble-shooting of his own this weekend.  It turns out that parameters had not been set for our non-bathroom rooms. Steve inputted some parameters for each room from our KNX system

 to the Domovea server.

After that, functionality of the actuators and values was restored.  We are back in heating mode.  We are still concerned about the transition to cooling mode and plan to send some more screen shots like this one to redblue Energy.

We are also struggling with the complex issue of obtaining a mortgage loan application for financing the house ("cash out financing").  We were speedily approved for a loan but the appraiser was unable to appraise the house because of the lack of comparables.  We are trying a different tactic:  our financial adviser at Morgan Stanley

has referred us to an entity that has familiarity with appraising green homes (http://starsloanservices.com/.)  We'll see how that works out.

 

In the meantime, we have been enjoying the property including our pond, the spectacular night sky

 

 

and the easy access to the pristine Western Maryland Rail Trail: 

 

 

Steve also captured this beautiful double rainbow which we think is a good omen for our new home:

 

 

 



Chapter 10 - A really smart house

Since my last post, Steve and I have been learning more about the energy features of our Plus Haus.  When we signed out initial contract, we purchased a KNX starter package to control our blinds and lighting efficiently and remotely.  We were aware at that time that the blinds would adjust automatically to a weather monitor mounted on the roof of our home.  Since then we have learned more about our 

Suntracer KNX-GPS Weather Station

 



The device has been installed on our roof above the solar array and looks like this:

  

 

 

It's smaller than we thought measuring only 96 x 77 x 118 mm and weighing approximately 170 g.

It measures temperature, wind speed and brightness. It perceives precipitation and receives a GPS signal for time and position. The exact position of the sun (azimuth and elevation) is calculated on the basis of location coordinates and time.  The data is used for the control of switching outputs for our shutters depending on preset threshold values.  For example, right now, according to Stephan Koschnitzke at redblue energy GmbH&Co.KG, the wind setting is fixed at a windspeed from about 17 m/s. After the speed is under the level, the blinds are blocked for another 5 minutes, then they go back to the last position.

From the KNX website (http://www.elsner-elektronik.de/klima-haus.html?&L=1):  The automatic control of shading and ventilation has long been standard in public and commercial buildings. This type of building automation is becoming increasingly important for residential buildings as well.  This amounts to a very smart house.

 

Speaking of climate control, since my last post we have also been successful with net metering via West Penn Power (First Energy).  Last weekend, Steve seredipitiously ran into a West Penn service technician who was looking for our well-hidden home.  Together they hiked up our 0.28 mile long steeply graded limestone drive way and the techician installed the type of meter that monitors the kilowatt-hours we are returning to the grid starting from zero:

 

 

Right now, we are working on establish remote monitoring of our PV system output using our Sunny WEBBOX with Bluetooth technology:

 

 

We haven't been able to get the web box to talk to our SMA inverters.  Any comments/suggestions from readers would be welcome!

 

We are also waiting to hear from hager (http://www.hagerco.com/) about the possibility of getting a US version of the iPad or Android app for the Domovea server to monitor our home both locally and remotely, as opposed to relying on the web-based application, although I am pleased with the speed of our DSL connection from Century Link (we have FiOS in Maryland).   

 

The snow has prevented delivery of our sinks and our home furnishings which will be coming from Room & Board (http://www.roomandboard.com/rnb/).

 This is what the house looked like last weekend:
 

 

 

Much better in terms of solar energy acquisition this weekend:



 

 

 

If you have a lot of stamina and love green homes, come visit: