The future of hydronice heating

Reading the posts in this form it becomes very apparent that in north America most heating systems are locked into the high water temperature as a way to delivery btu to the heat emitters. This way of heating was a natural path in the day of low fuel cost. The physical part is fairly easy to correct ,just add more heat emitters, the more difficult part is to change how those in the heating business think. Heating with 100f water or less sounds crazy. What happens when we heat with 180f water is the air in the room is the first thing to be heated and the first thing to leave with your btu and dollars , is the least comfortable. If we heat with low temperatures , everything in the room becomes warm as the btu are deposited in the objects and they don't leave, the result is more comfort and cheaper fuel bills. There is of course a lot more to this way of heating ,some call it The future of Hydronics.

 

Over in Germany my in-law's relatives heat this way. The house temperature is controlled by the boiler's water temperature. There systems are light years ahead of ours making this practice the norm and ours ancient history.

 

I believe the reason most of Europe seems to have higher tech heating systems is for at least two reasons...

1. Government mandates higher efficiencies.

2. Fuel costs MUCH more, so consumers gladly accept government mandates.

We're getting there... I promise... wait for it ...

 

I think it's relatively well known that the road to highest efficiency is a water temperature modulated constant circulation system with indoor temperature feedback.

 

Precisely why I believe that government bureaucrats are not capable of looking out for the best interests of us regular folks in this regard.

Over the past several years the US government has done pretty much nothing about artificially high (IMO) energy costs, particularly oil and electricity, other than propose (and impose) more regulations and tighter efficiency standards (i.e., try and force people to purchase more complicated, expensive HVAC systems and pay higher electric rates). I would argue that current government energy policies have in fact contributed to the greater economic pain people feel at both the gasoline pump and their fuel oil tank. But that argument is for another day.

My point is: be careful what you wish for. High-efficiency HVAC systems sound wonderful in theory - until you factor in the higher costs of acquisition, installation and maintenance. Not to mention all the additional rules and regs. that homeowners and contractors have to wade through. And then of course there is the very strong possibility that your new mod-con boiler that was advertised as "95% efficient" doesn't really operate to that efficiency level after all. Certainly not all of the time, and probably not even most of the time.

 

Appreciate the comments here. Here's my 2 cents.
While I talk to contractors, reps, distributors and homeowners all over the country and Canada. Here is what I think.

First let's clear up the Europe saga, about 70% of new boilers sold are still cast iron boilers. Very similar numbers here in the states. They do things much different than we do.

As usual our government offers rebates on the wrong thing. They should have forgotten about boiler efficiency rebates. The rebates should have been on proper boiler sizing and proper installations.

I know 80+% of all boilers installed are at least 100% oversized. I will guess that 70% of those systems are micro zoned which will cause short cycling and lower efficiency. Many 95+% high efficiency boilers are installed without OD reset even though it is supplied with the boiler. I would venture to guess that 95% or more boilers with ODR the settings are still at factory settings which are higher than they need. When high efficiency boilers are installed with IWH's the boiler DHW input rate is left higher than the tank can handle causing more short cycling and boiler water temperature overshooting.

The highest fuel savings us accomplished by properly sized and installed equipment beit boiler or furnace. The second largest fuel savings is properly adjusted ODR which majorly raises system efficiency.

Another problem is system flow. Most systems have too great a flow in the system. If you use multiple pumps on a non-primary/secondary system there is a good possibility the boiler is over pumped especially if the boiler is properly sized. For instance a 60k boiler can only flow a maximum of 6 GPM or the btu transfer is reduced and less heat output from radiation is experienced. Two pumps could possibly move 8 GPM. The boiler delta-T is less than 20f.

I feel multiple pump jobs should by piped p/s (primary/secondary) if system flow can exceed boiler flow. If the boiler is a mod/con with a higher flow rate causes the boiler to run at a higher input to get the delta-T and set point temperature the boiler desires.

Unfortunately as the weather gets colder you have a better chance of more pumps running and each gallon of water that flows through the boiler above the resting will pick up less heat than a boiler operated at the proper flow.