Energy Efficiency in Hydronics Part 1

John Ruhnke

When it comes down to Energy Efficiency in a Hydronic Heating System the Goal of a Heating Contractor/Designer is to use the most amount of energy from the fuel to heat a conditioned space. Energy is lost in several ways.

A Good Heating Designer considers the following 7 points when designing a Hydronic Heating System.

1) Through the chimney or exhaust gas of a boiler.

2) Air movement through the combustion chamber when the boiler is not firing.

3) Jacket Loss's from the boiler and exposed pipe loss's that make boiler rooms hotter then needed.

4) Over Heating of a conditioned space by way of unbalenced distribution of heat emmiters.

5) Heating a unconditioned space by distribution piping.

6) Over Heating a outside wall or wall butted up to unconditioned space with a heat emitter.

7) Heating outside walls or a wall butted up to unconditioned space with distribution piping.

Heating System Efficiency can be broken down into three parts.

1) Fuel Efficiency

The first step is to look at how efficient the fuel is that you are using. Oil, Gas, Electric, Geothermal, Solar, Fuel Cells, wind or CHP.

2) Boiler Side Efficiency

This is the loss's of the equipment in the boiler room. Of the above 7 points this involves the first three.

3) System Side Efficiency

This involves the last four of the above 7 points.



In my next post I will talk about fuel efficiency. I will first need to learn how to upload some power point slides.

Gordy

The Shell

I think # 1 Should be the thermal efficiency of the envelope John.



It all starts there. The need for the comfort system, and size is dictated by the losses/gains of any envelopes enviroment you are trying to control.



You can use the most efficient fuel,boiler,and emitters in a non efficient envelope.

You can have the most efficient envelope with a sub par heating cooling system.

In the end the envelope, and comfort system work together to give the occupants comfort, and the best efficiency Possible. the two are in deed one system, or maybe sub systems.



Gordy 

John Ruhnke

RE:

Gordy,

The envelope is a different topic of discussion. Yes it is very important. An envelope designer could go over the efficient use of insulation. A Jack of all Trades is Master of None. We are heating system designer/contractors. The differences in fuel use from changes in the design of a heating system are just as important as changes in the envelope side. The only problem is that the difference's on the heating side are ignored by the public and most experts. Because the experts ignore it. Its almost like the problem doesn't exsist. There is a huge lack of education and research being done on heating system efficiency. Most of the time the experts are pointing people to go in the wrong direction. As I continue with my posts in the future you will see what I mean.

Jean-David Beyer

There is a huge lack of education and research

"There is a huge lack of education and research being done on heating system efficiency."



Are you sure about that? There seems to be quite a lot of information on that. It may be that some contractors are ignorant of it, and most homeowners besides. But it is out there. Licensed Professional Engineers who specialize in heating systems are surely aware of this information including the current research.



In fact, it seems to me that it is the efficiency of the total system; i.e., the building and everything in it, that matters. What difference does it make for me to replace an 89% efficient boiler with a 95% efficient one in a house with leaky windows, little or no insulation? In fact, if I had one of those, would I make greater total cost of ownership reduction by putting $5000 into a new boiler or insulating the place? I admit that each house would have to be studied individually.



In my case, I put about $2,500 worth of insulation in my house in the early 1980s. That made a big difference in my heating bills. A few years ago I put $12,000 worth of Marvin windows (double glass, argon filled, Low E coating) in. I have no doubt the efficiency of the building increased, but I cannot tell if it reduced my heating bills or not. They now open, so I can cool off the place in the summertime, which I could not before with the @#$% cheapo 1950s aluminum windows that came with the house.



My latest escapade is to put a mod|con boiler with outdoor reset in, converting from oil to gas. I do not really know the efficiency of the old boiler, but I doubt it was over 70%, and it cycled quite rapidly. As we squeeze the stone more and more, the last little bits are more and more difficult to obtain.

John Ruhnke

RE:

JD,

First off. If your heating system is functioning at 70% you would have one of the best heating systems around. It might be running at around 20% or worse most likely. 20% Overall Efficiency that is. That is one of the biggest problems. Experts look at AFUE and they think there is not much room for improvement so they don't spend the needed time or money researching. Dr Tom Butcher is a friend of mine. We chat once in a while. Tom is in charge of Energy Efficiency Buildings for the DOE at Brookhaven Labs. Brookhaven is one of 10 national DOE labs in our country. The DOE is not even funding Tom right now. Tom is funded mostly by NYSERDA and privet companies. Sure the DOE is spending billions on everything else from Geothermal, Solar, Fuel Cells and more. Tom is heavily handicapped right now and his dept is the only dept in all of the DOE that does what he does. I am helping Tom to succeed right now but nobody is paying me.

Gordy

Hand in Hand

 John my point is the same as JD's. It all starts with efficient design at both ends.



For new design homes there needs to be a relationhip with the designer, and all other mechanicals in the design stage if they even care about effciency.



Governments need to step in fed, and local to impose high standards for envelope efficiency. If you wanted to build a house with no insulation, and single pane windows nothing could be done to stop you. At least in my area.



It does you no good to put a 40 mpg engine that was designed for a certain body style car in a tank expecting 40 mpg.



Now if you want to stick to efficent hydronics systems as a whole thats different, but in the end it does not matter if the shell is not the best it can be.



Gordy

Jean-David Beyer

If your heating system is functioning at 70%

I do not say you are wrong, but you are clearly measuring in a different way than I do. (Actually, I do not measure it at all, but go by the manufacturer's ratings that are AFUE, with the limitations we mostly know about.)



However, when you say my old GE oil burner from the 1950s with a 1980 Beckett burner in it was only 20% efficient rather than 70 %, there is clearly a huge difference, and I do not think the limitations of the AFUE measurement can account for it all.



So how does your "Overall Efficiency" differ from the AFUE? What do you measure that AFUE leaves out? In my case, the boiler is in the garage, so the heat lost from the boiler to its surroundings is one that is not included in the AFUE rating. In my old boiler, that waste heat did melt the snow from my car overnight, but I will not get that benefit from my new boiler. But you must be measuring some large other losses that I am unaware of. What might they be?

John Ruhnke

RE:

Gordy,

Technology works best when experts of different fields come together. It is best to take my knowledge of hydronics and combine that with the knowledge of others. Go out and find a forum on insulation and I am sure you will learn a lot there.

Jean-David Beyer

Thermally efficient buildings.

I worked in an industrial research lab for a long time. The building I worked in was so thermally efficient that they seldom added extra heat. Back when Nixon, I believe it was, imposed energy controls, he said we had to let buildings get up to 78F or something in the summer, and keep them under 68F or something in the winter. The funny thing is that the heat load generated by the equipment was so large that we would have had to run more air conditioning even in the winter to keep the temperature that low. I had a large minicomputer in my lab that required supplementary air conditioning all year long. In the lab next to mine was a furnace used to make semiconductor chips. It ran extremely hot and they blew hydrogen through it to keep things from oxidizing, and other gasses such as Arsine, Phosphine, and Hydrogen Selenide that are way more toxic than Hydrogen Cyanide, so they had a constant flame burning at the output of the furnace to burn them away.



It is interesting to think that if I spent enough money to insulate this house completely, I would have to cool it year around. Right now it is 66F outside, and it was even cooler last night. Yet the heat loads are such that this room is currently at 77F and I have not been heating it with my heating system, just the waste heat from the computer (about 600 Watts), and come compact fluorescent lights.

Gordy

Insulation

John I know plenty about insulation. When Aerogel becomes cost efficient to produce look for big changes in the window, and building insulation horizion, and semi conductor industry.



You are somewhat preaching to the choir here, Been frequenting this site for 10 years, The majority are in deed consious about putting in a system that is as efficient as can be with the dollars they have to work with.



Please share some concrete evidence of these system efficiencies of 20% John.

Gordy