Jumping into hot water again

By Tom Gocze, BDN Staff
Posted July 24, 2009, at 8:20 p.m.

I have spent a fair bit of time messing with solar and wood boiler heating systems. We have built hot water storage tanks for years and recently developed a new water storage tank for a wood boiler company.

Since I get to mess around with fire and water — a great job — it seemed time to install a new heating system in my home. (It has been almost five years since the last one.) My long-suffering wife has endured a LOT of heating systems over the years, some being better than others. These changes used to happen in January; this year I am starting early.

This heating system changeover has been an exercise in procrastination for a while, but last week it finally came together.

I installed a 345-gallon heat storage tank in the basement. The tank is sized for a solar heating system. I think we can run mostly on solar through the winter. At least that is the plan. The backup plan is to install a small wood boiler to heat the tank in case the sun doesn’t shine. We historically have 50 percent sunny days in Maine. But we have only 40 percent sunny days in December, the coldest and least sunny month of the year.

So we plan for backup. A wood boiler will allow us to store heat for later use. A wood stove is still there for backup if the power goes out, but otherwise would not be used much.

This is getting complicated, but there is one more thing to add to this heating melange. We installed a Nyle Corp. heat pump water heater to heat the tank during the summer. Since we do not have the wood boiler or solar installed yet and the tank is here, it seemed prudent to heat it with something.

I have used the heat pump for two years to heat my hot water in the summer — once I realized that it is cheaper to operate than our oil system. The beauty of the heat pump water heater is that it dehumidifies the house and also air-conditions while making hot water. This is a win-win situation in the summertime, especially on the coast. And the Nyle heat pump water heater is manufactured in Bangor.

There is a method to the madness of heating 345 gallons of hot water with a heat pump. First, I get to test how much heat loss occurs off the big tank by comparing the performance against a smaller tank and, second, if we ever get a smarter electric grid, this type of system might be important.

The concept of storing heat is really one of storing energy. Storing hot water is a lot simpler than storing electricity. This is a tool that an electric utility company can use that allows it to shut off the heater at certain times of the day. The consumer allows the utility to do this in return for a big break in electric costs. Since water heaters use a lot of electricity, this is a simple way for a utility to control the customer demand.

A 345 gallon (or perhaps a 150-gallon one for a more realistic “normal” installation) tank allows you to operate for a significant period of time without running out of hot water.

These types of systems were tried in the 1980s with mixed success. What is different today is the air source hot water heater. The air source heat pump has the ability to cut the fuel cost to less than half that of a conventional electric water heater, and it is simple to install.

We will be reporting on the heat pump performance over the next couple of months. In the past, using an 80-gallon tank with no backup kept our family of two in ample hot water for $20 to $30 a month while keeping the basement blissfully dry and air-conditioned. It is a simple matter to duct this into other parts of the house as well.

The water part was fun, but I suspect the fire part will be even better.

Questions for Tom Gocze should be mailed to The Home Page, Bangor Daily News, P.O. Box 1329, Bangor 04402-1329. A library of reference material and a home-project blog are at www.bangordailynews.com/thehomepage.html.

http://bangordailynews.com/2009/07/24/living/jumping-into-hot-water-again/ printed on September 16, 2014