Hot water space heater and Tankless

[redbarron55]

I think that the task is doable but I don;t have time right now to do anything but plan and perhaps collect some parts and pieces.
The Tankless Fastar has a thermostat included (but it reads in Celsius so I will need an interpreter) that will let me dial it in.
Usually we are just looking to take the chill off the trailer and this is really a back up for the heat pump (and an excuse to fiddle with stuff).
At the same time a circulating system with the tap off the sink how water will keep hot water there with no waiting, same for the shower.

[Iowan]

Originally Posted by Raspy

There is no connection between car engines operating most efficiently at 195 degrees, and the heating requirements of a camper. And there is no connection between car cooling systems and scalding tap water. I've never felt the need to run a home heating system, or my sink faucet, based on the temperature of my car engine. Not sure how one compares to the other or why it should. BTU delivery is determined by a number of factors, only one of which is input temp. When starting from scratch, and not using the car as the heat source, one can adjust any of the parameters as desired.

You missed the point! Its not the 195 degree efficiency of an engine. It's the temperature loss between that and the air temperature output at the heater core. Also the water volume flowing through the core. I would think it would take a fairly large core and pump to deliver enough BTU at normal water system temperatures. But then you must know.

[redbarron55]

A 16' Scamp has a relatively small space to heat, but then there is also little insulation there.
The Fastar is rated about 80,000 BTU or 24 KW.
a 1.5 KW electric heated will do a pretty good job of heating the little camper so I don;t think that the heat output from the heater is a problem.
Now the question is the heat transfer rate from the radiator and water flow.
We are looking for a heat in the trailer of about 70 degrees so a water temp of 102-4 would transfer some heat. Since the water is recirculated and heated to bring it back up to 102 after passing through the heater the second time ??
All I know is that domestic hot water heaters can handle it in apartments.
The reason for the experiment is to determine how best to do it.
If it is below freezing the hot water heater would be drained anyway so it would probably not be used then.
But the if it were running it shouldn't freeze maybe?
I look forward to getting started later.