Steam to Hot Water Retrofit / Conversion
Steam to Hot Water Retrofit / Conversion
(OP)
I'm investigating the feasibility of converting an old steam system (circa 1980) to hot water. This is part of a major HVAC retrofit, and the goal is to do this as cheaply as possible. I've heard rumors that it's possible to retrofit steam coils and piping networks for hot water, at some reduced capacity, but I haven't been able to find any information on this.
Has anyone been involved with a project where this was done? Do you know of any articles / case studies about this? Please advise.
A little detail on the system:
Large air handling units (AHUs) have low pressure steam heating coils. Replacing the coils and piping may be cost prohibitive. Total heating capacity is about 2500 MBH. Most existing steam coils are over-sized by 100-800% based on recent peak load analysis.
Has anyone been involved with a project where this was done? Do you know of any articles / case studies about this? Please advise.
A little detail on the system:
Large air handling units (AHUs) have low pressure steam heating coils. Replacing the coils and piping may be cost prohibitive. Total heating capacity is about 2500 MBH. Most existing steam coils are over-sized by 100-800% based on recent peak load analysis.





RE: Steam to Hot Water Retrofit / Conversion
RE: Steam to Hot Water Retrofit / Conversion
RE: Steam to Hot Water Retrofit / Conversion
RE: Steam to Hot Water Retrofit / Conversion
Most steam boilers can be converted to hot water, but many, many, many things other than the boiler must be changed/replaced top convert to hot water, ie, piping, valves, controls, terminal units and etc.
RE: Steam to Hot Water Retrofit / Conversion
seriously though, I would not utter one word on possible solutions (retrofit) etc until all the homework is done. I learnt that the hard way, opening my mouth and not putting the appropriate caveats out at the same time ie spatials, budget, service access.
RE: Steam to Hot Water Retrofit / Conversion
I'd be willing to bet that for a fraction of the conversion cost, you can make your existing steam system almost as efficient as the proposed hot water conversion.
Good luck.
RE: Steam to Hot Water Retrofit / Conversion
How a bout the coil connections? None of the existing steam valves can be reused. All of that will have to be replaced for proper hot water usage.
What about the piping? If it is even possible to reuse the steam and condensate piping (very hard to believe you could), the size of pump for connecting would be outrageous. The artificial head from the triple-duty valve would be so bad you might not even be able to balance the system.
As an engineer, I wouldn't touch this without replacing the whole system. Keeping the boiler may be the only cost savings available. But now you have control changes and a new relief valve to install.
RE: Steam to Hot Water Retrofit / Conversion
very nasty black sludge that will be coming loose and circulating in the system,clogging valves,air seperators etc...
solution? water treatment to clean out the sludge.
however, the sludge is most likely sealing leaks in the system.
add this to the increased pressures you will encounter with hot water, and there will be leaks everywhere.
I have been involved in these types of projects before and they never turn out good.
Can you say change order?