Geothermal Heating and Cooling- It’s affordable, it works, and it’s reliable

I got my start in Geothermal about 7 years ago when a call came it to fix a ‘mystery’ radiant floor heating system. Upon arrival I immediatly recognized the system as a Geothermal heat pump. The fix was simple, the system lost flow and caused an overload. I replaced a few wires and the client was up and running again. Our new client was so happy to have a working system that he asked if we could go through the system and work out more glitches.

At this point I had zero experience with ground source heat pumps, but was dumb enough to try anything. That night I took the installation manual home and read it cover to cover. After reading the manual, I found that his system really wasn’t compatible with the heat pump itself. He had a storage tank that was massively oversized, a radiant floor heating system that couldn’t maintain proper flow rates, and the ground outside was freezing. We made a few piping changes and installed a properly sized storage tank. Within one day, his house was maintaining 70 degrees which he claimed hadn’t happened before on a 30 degree day. A big problem was the geothermal field though, after reviewing the as builts, it was clear that the field was undersized according to my rough calculations. We ended up having to increase the size of his backup boiler to maintain a comfortable indoor air temperature, not ideal.

This service call turned into a new passion for me. Before getting my feet wet, Geothermal heating was mysterious and I thought the industry was ‘gimmicky.’ But in the coming months, I found myself troubleshooting Geothermal systems as far as 80 miles away. I came to find that there were allot of folks with pieced together systems that had just a few critical components that if done properly from the start, could have been great systems.

One major theme that seemed to be universal was that I either saw systems that had great ground work but poor indoor heating systems or the converse. One in particular humored me when I happened to be driving by a super ‘green’ house that was giving tours. Upon entering the home, I couldn’t help but go straight for the mechanical room. I saw a very well installed Geothermal heat pump connected to a radiant floor heating system that was, well, not so very well installed. You see, the Geothermal heat pump could deliver water temperatures around 110 degrees reliably. The radiant heating system however required water temperatures of 140 degrees. Uh oh, that meant that the Geothermal heating system could only supply heat to the house if the outdoor temperature was above 45 degrees. Why even go there?

It’s not rocket science, but just like anything new, you have to pay your dues and learn to do it right. Because I’ve been in the hydronic heating and pumping industry my entire adult life, Geothermal came easy, but not without paying my dues. I had to learn about new things that I didn’t anticipate, like soil.

There are many ways to absorb energy from the earth. Geothermal simply means ‘relating to the internal heat of the Earth.’ If you are lucky enough to live be a hot spring, you can simply pipe that hot water into your house and have all the free heat you want. Other than a few hotels, I’m not aware of anyone who so lucky. Most of us use a heat pump which absorbs energy from the earth by circulating a fluid through a series of pipes in the 45-55 degree earth and compresses that energy into a useful form. The compression process uses energy and this energy is measured by COP (coefficient of performance), sounds complicated, but it’s pretty simple. COP is the ratio of the heat output rate from the heat pump divided by the electrical energy input rate to operate the heat pump. For example, it a heat pump has a COP of 3.0, that means that for every watt of electricity you put into it, it will give you 3 watts back.

How does this all translate into energy savings? Well, there are 3 factors as I see it. #1 is the price of electricity compared to any other form of energy that might be cheaper and available, per unit, measure by measure. #2 is the savings from the heat pump, and #3 is the enhancements made to the indoor system to make the Geothermal energy usable. Sounds like allot but let me break it down.

For this example I’m going to use the last house that we installed Geothermal into. The house was heating with Propane, 3300 square feet, and modern construction. The propane operating costs are around $3,200 per year, and the operating costs with Geothermal were around $700 per year for an annual savings of $2,500. In this case the Geothermal system increased the installation cost by $13,000. Without rebates the payback is 5.2 years. However, uncle same chips in another 30% tax credit. So that particular investment only gets better. I don’t want to jade you however, this house has unique factors. In most cases Geothermal has a 10 year return on investment. Combine that with your federal write off and the payback is downright affordable, even if you have natural gas.

Let’s talk about the gear for a moment. In order to absorb energy from the ground, you need ground. The cheapest system by far is a horizontal field. Typically this field is going to require a minimum of 5,000 square feet of free and clear land available. Chances are, if you don’t have 3 acres of land, this option isn’t available. The most common alternative is to drill bore holes vertically. Typically you need 800-1100 feet of bore length to heat the average home which translates into 4 or 5 holes at varying depths. Other systems include open well systems that use ground water for heat transfer, and pond loops, both of which have difficult permitting process’ and are avoided in our area. However, MMI is currently working on making the permitting process a little easier to swallow.

I want to talk about drilling for a moment. Until now, drilling costs generally put the payback of a Geothermal heating system in the 20-25 year range. That is because we drill water wells instead of Geothermal wells. What’s the difference? Water wells require a steel casing to be pounded into the earth that serves no purpose in a Geothermal system. A Geothermal well isn’t cased, can be drilled quickly, and costs much less to install. MMI, is currently working with a drill team that utilizes this technology and our vertical well systems are about half of the price of our competition. And the systems have the same or better performance. The payback? Less than 10 years if you include your federal tax write off. This means that we can generally utilize a “postage stamp” size lot in the middle of the city.

Thanks for taking the time to learn about Geothermal heating. Feel free to contact us anytime for a savings and feasibility analysis. MMI has a great record for installing Geothermal and we look forward to serving you.

Josh Mitchell

Solar PV Job

Mitchell Mechanical is in search of an electrician that is interested in running our future solar PV department. The preferred candidate will have their masters electrician license and will also have had experience installing solar PV. We are growing rapidly–and forsee a large # of future jobs integrated with solar PV. This is a huge opportunity to become a partner in a growing company where your success growing the PV department will correlate into substantial earnings. We will create all the marketing support and leads though in the beginning you will be asked to do all things related to electrical equipment hook up. Please contact Geoff McBride for more information. Geoff@mitchell-mechanical.com

Solar Thermal Hot Water System in W. Seattle

Greetings,

This system was installed on my own home in W. Seattle on May 3rd and 4th.  It consists of 2 Viessmann flat plate collectors, 1 Superstor ultra 80 gallon buffer tank with duel coil, 1 Caleffi pump station with I-solar control, mounting racks, hardware and solarflex insulated tubing.  The solar thermal was integrated with my radiant heat system.  I had an existing Takagi tank-less hot water heater and a staple up hydronic radiant system that runs at 150 degree supply temperature.  Early May was still cold yet the 80 gallon solar thermal tank was still getting up into the high 80, low 90 degree water temperature range.  When there was a call for heat from the radiant system–the tank-less water heater was getting 90 degree water (approximately) vs. the normal street temperature water (55 degrees).  I noticed right away that the Takagi wasn’t having to come on full blast–it was much quieter–modulating its btuh output to bring 90 degree water up to 150 degree rather than 55 degree up to 150 degrees.  On sunny days (like this past Memorial day weekend)–the solar thermal system was consistently getting my tank up to 155 degrees or so.  We have had no call for heat lately from the radiant system due to the great weather–and we are also not using 80 gallons of hot water every day–so our tank-less heater hasn’t even been running at all.  I got my PSE bill yesterday and compared it to last years natural gas therm usage.  Last year’s cycle had 32 days vs. this years of 30 days (I believe PSE forecasts usage for the final week in order to send the bill out late in the month).  Anyway–last year we used 84 therms of natural gas for May–and this year we used 53 (with the last week a forecast based on daily use).  Even with the 2 extra days–that is pretty substantial.  I think, up until the last week and a half or so–that the weather was cooler this early May vs. May 2008.  I look forward to comparing the month to month natural gas savings and can’t wait to have a full year in perspective.  I enjoy going home from work at night and looking at the control to see how the day’s harvest has gone.  It is pretty fun and we are saving money.

Resources we have found helpful.

http://www.epa.gov/climatechange/emissions/ind_calculator.html (Provides a ballpark estimate of your families green house gas emissions)

http://www.dsireusa.org/incentives/index.cfm?CurrentPageID=1&State=WA&RE=1&EE=1 (Shows what energy incentives are available at the Federal, state and local level)

http://www.energystar.gov/index.cfm?c=products.pr_tax_credits#c3 (Summary of tax credits for homeowners)

http://www.carbonify.com/carbon-calculator.htm (A carbon dioxide emission calculator)

http://www.myamortizationchart.com/ (Handy mortgage calculator which can help you figure out what an investment in efficient equipment will cost monthly if you financed it through our Sunbridge loan program) . Remember–all $ that we pay to the utility can be viewed as interest–it never goes to pay anything off. Financing energy efficient equipment that lowers your utility bills, whether that be a solar thermal, pv, heat pump, boiler, efficient furnace, air handler, HRV,control system etc -is a good way to go because you eventually pay it off. You never pay off the utility. It is also an investment in your home and gets us all closer to energy independence.

Thank you Seattle!

The Seattle Home Show was firm recognition for us that our product offering is exactly what more and more people are interested in for their home heating and cooling systems. Our solar thermal evacuated tube display caught a lot of folks attention. Ranging from pure curiousity to folks that already understand the vacuum tube technology–lots of people stopped to look at the tubes and ask questions or offer their own insight. The other two products we featured that caught a lot of buzz:

Featured Product #1: Unico Unichiller (Hydronic Heat Pump) manufactured and produced by The Unico Company.

The Unico Unichiller is a heat pump—with a twist. All heat pumps function well at low temperatures. Air to air heat pumps are capable of raising the air within the house 20 – 28 degrees when the outside air temperature is about 45 degrees. So if the indoor air temp is 66 degrees, the discharge air temp (DAT) in a duct system will 86 – 94 degrees. This is called temperature rise. At a 32 degree outdoor temperature the temperature rise with an air to air heat pump is around 12 – 15 degrees. With a DAT of 78 – 81 degrees the heat pump may never shut off even though it is producing BTUH’s . Refrigerant is such a poor conductor for heat at low temperatures that we shut heat pumps off with an outdoor thermostat and switch to back up heat in order to actually satisfy the indoor thermostat. This has been common practice during the winter of 2008-2009 which has devalued the efficiency of the air to air heat pump.

The Unico reverse cycle chiller (RCC) produces water temperatures of 110 – 125 degrees down to 10 F outdoor temperatures. This makes the temperature rise in a RCC system 40 – 50 degrees, like a gas furnace. The DAT in a RCC air system will be 105 – 120 degrees, even at low outdoor temp’s, which will satisfy the indoor thermostat. Water is an excellent heat transfer device. Unlike a gas furnace that at best operates at 95% efficiency (even with the most recent advancement in furnace technology)—the Unico RCC’s COP is 2.3 down to 17 degrees F. COP stands for coefficient of performance and it is a measure of how much energy is input vs. output. In this example, for every 1 KW of electricity input into the RCC—it yields 2.3 KW. That is 230% efficient even at very cold temperatures. That is very impressive and extremely efficient! Mitchell Mechanical has installed them in 6 different residences to date with exciting results. We already have 9 more slated for installation by summer of 2009 with many more proposed. Learn more about them here: http://www.unicosystem.com/Home/Products/UniChillerRC/tabid/80/Default.aspx

Featured Product #2: My Temp (zoning control system) manufactured and produced by Home Comfort Zones.

A typical home in the NW with a forced air heating/cooling system has areas in the home that can be much colder or hotter even thought the central thermostat says it is, say-68 degrees. We’ve all experienced and bemoaned this problem. The MyTemp system is not a replacement for your furnace or air-conditioner. You don’t have to replace your furnace and rip out your entire duct system to be comfortable! It is a room-by-room temperature control system that uses your existing heating and cooling equipment and ductwork.
When the MyTemp system is installed in your home, a wireless smart controller is placed in each room. It continuously measures and transmits the room’s temperature. A wireless receiver collects this information and passes it along to the master control unit (which replaces your current thermostat). Using temperature information from each room as well as temperature data from an outside monitor, sophisticated software determines which rooms need conditioning.
Using air pressure and vacuum supplied from an external air pump and power supply, individual rooms are included or removed from the conditioning cycle by opening and closing dampers in the duct work. The master unit then activates the heating, cooling, and circulation equipment in your home to achieve your settings. Using information from the plenum sensor, the master unit can determine how many dampers can be simultaneously closed without effecting your equipment. You can control where you want your heat or cooling room by room. Save energy—don’t heat or cool rooms that you aren’t using. This system is retrofitable. We can literally take an existing home that has this problem and fix it in one day—making you more comfortable and saving you energy at the same time. Mitchell Mechanical is a licensed and trained dealer and we have several systems installed to date with fantastic testimonials. Learn more here: http://www.mytemperature.com/

So–thank you Seattle and thank you to all who visited us at the Seattle Home Show! We had a great time and look forward to being there again next year.

Staying Busy

It has been awhile since the last post. We have been working at full throttle trying to keep up with the demand for our services. We have doubled our size in 6 months. The residential market has slowed way down so we have been focusing more of our attention in the commercial sector and gaining traction.

We are also working our tradional core business in the custom home marketplace. This business has remained steady for us but we have put quite a bit of effort to keep it steady as the overall marketplace has slowed dramatically.

We will be attending The Seattle Home Show Feb. 14-22nd and hope to see you there! We are really excited about the future of this business and hope that the new administration will make it easier for people to adopt newer, more efficient technologies that also help keep our environmental impact to a minimum.

While we are all focusing on growing our core business–but you can still find Josh Mitchell over at the Seattle Mariner’s from time to time working on their industrial boiler system.

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A Zero Energy Idea House

What does zero energy mean? We’ve been thinking about that a lot lately. One of our big goals as a company is to make homes & businesses self-sufficient from an energy use standpoint. However–one of the components in this equation in respect to true energy ‘cost’ is that you need new energy efficient equipment to get close to zero energy. When we talk about zero energy we just mean the amount the house needs to operate in respect to heat, cooling and electricity. The energy inputs–the energy it takes to make the new efficient equipment should also be a consideration in the overall system design, performance and equation of energy use.

We want to make sure that the systems we design have an energy payback both for the equipment ‘energy inputs’ and for the energy the system can save over its lifetime vs. your current one. Our goal is to make that breakeven point less than 10 years as the equipment we install can last up to 30-40 years. A 3-1 ratio is pretty good.

Competitors that don’t think about energy inputs or skimp on components really are doing a dis-service to us all. As a society that is really just starting to face the reality that much of the energy we rely and depend on is finite (fossil fuels)–it is imperative for us to start thinking longer term. It would be nice if we would all start to pay attention to the cycle of products–and understand that if we buy cheap products and systems–then they are more likely to underperform from an energy standpoint and also breakdown sooner than they should. This costs everybody money. If we all start to think longer term–and build superior systems on the front end (they don’t cost that much more than inferior systems)-then we will not only save energy but also money that would go to buy new equipment much sooner than necessary. If it always boils down to dollars up front–then systems will continue to be designed poorly and underperform. Expertise and knowledge always cost a little more up-front but pay for themselves many times over in most situations.

Back to the main subject. We have been invited by Shirey Contracting in Issaquah, Washington to design and build their energy system for their personal home. They are a likeminded company that believes in better products and building structures–and they are very interested in energy and efficiency. We have designed a radiant heat system for this 1,800 sqft home that works with a product called a Reverse Cycle Chiller. Despite the crummy name–Reverse Cycle Chillers (RCC) are an amazing technology that work very similar to a traditional heat pump. Instead of transfering air to air (like a traditional heat pump)–the RCC transfers the heat from air to water or from water to air to be used in a radiant heat or forced air system. The RCC operates on a 3-1 COP (coefficient of performance) meaning that it produces 3 x the amount of energy in requires to operate. Again–3-1 is good! Something incredible happens when you transfer heat to water!! Solar Photovoltaics will be added to the roof of the home to produce the electrical needs of the RCC and the majority of the electric loads of the home. A solar hot water system will also be installed to produce approximatley 70% of the yearly domestic hot water needs. To finish it off, a high efficiency electric water heater will make up the difference.

This type of integrated system is our passion. The technology is now available to make almost every new home self-sufficient. Does the system cost more up front–yes of course. But does the system save money during its expected lifetime–yes—and in most cases the energy money it saves is dramatic–and that is not even considering energy inflation. Right now–we all pay the utility whatever they demand of us. None of that money is ever given back to us. We aren’t paying anything off. They control the prices. However, if we all buy a better energy system–even if we finance it–there is a principal and interest payment—which means it eventually gets paid off and then you get your energy for free. We never get to pay anything off with the utility and their energy is never free.

The technology is available today to make our homes sustainable. This is an exciting time for our industry and for our environment.