district heating system Inflow Vs Return temp issue

Roddylarge

Hi i was wondering if anyone here can tell me if I'm being stupid or not.

Our house works off a district heating system.

Its a new build house A3 energy rating and since We moved in over the summer, so its only now that its got cold that we have had to use the heating. I noticed however that its working out more expensive than i thought to heat the house.

I did a bit of investigating and noticed that the inflow temperature (coming into the house from the district heating system) is 70c and the return flow (leaving th house) is 59c so a delta of 11c.

Does this mean that the majority of the hot water that i am paying for to heat my house is being returned? This doesn't seem very efficient if that is the case. I thought that the return flow should be around 20c and the temperature difference was what was transferred as heat to the house. Have i got this wrong? is there anything i can do to resolve this if it is an issue?

one other thing,
we have a small front living room. I took the radiator off to paint about a month ago and have just put it back on. This rad heats up so that it is too hot to touch, but the core temperature of this room still feels cold compared to all of the other rooms. Should i need to adjust the lock shield in order to solve this?

hopefully someone can help.

Dtp1979

Roddylarge wrote: »

Hi i was wondering if anyone here can tell me if I'm being stupid or not.

Our house works off a district heating system.

Its a new build house A3 energy rating and since We moved in over the summer, so its only now that its got cold that we have had to use the heating. I noticed however that its working out more expensive than i thought to heat the house.

I did a bit of investigating and noticed that the inflow temperature (coming into the house from the district heating system) is 70c and the return flow (leaving th house) is 59c so a delta of 11c.

Does this mean that the majority of the hot water that i am paying for to heat my house is being returned? This doesn't seem very efficient if that is the case. I thought that the return flow should be around 20c and the temperature difference was what was transferred as heat to the house. Have i got this wrong? is there anything i can do to resolve this if it is an issue?

one other thing,
we have a small front living room. I took the radiator off to paint about a month ago and have just put it back on. This rad heats up so that it is too hot to touch, but the core temperature of this room still feels cold compared to all of the other rooms. Should i need to adjust the lock shield in order to solve this?

hopefully someone can help.

If the boiler is condensing then you'll get a 20 degree differential and 10 for bob condensing. But those temps will change as the water is beem heated for longer. What are your stats set you?
The issue with the rad is that it's probably undersized.

Roddylarge

I don't have a boiler in the house, just a series of pipes coming in and out. The boiler for the estate is situated further down the site so I'm not sure if its condensing or not.

The stats for both downstairs and upstairs are set at 20c.

As for the rad issue, I'm wondering if the room just needs a few days heat to take the chill out of room as it hadn't been on for about a month.

Sleeper12

Roddylarge wrote:

As for the rad issue, I'm wondering if the room just needs a few days heat to take the chill out of room as it hadn't been on for about a month.

Much more likely undersized rad. You might be able to replace it with a double if its a single without altering the pipe work

Pete67

You should have an energy meter installed in a house connected to a district heating system. The meter measures both supply and return temperatures at the point of supply to the property, along with flowrate, and from this data it calculates the total heat energy consumed by the household in kWh. From a billing point of view, it does not matter what the supply and return temps are, the meter measures the actuals and calculates accordingly.

A temperature drop of 11C sounds about right. You should receive a bill from the operator of the district heating scheme showing the number of kWh consumed, along with details of the unit rate and any standing charges.

Roddylarge

But we have the same sized rad in another identical sized room and there is no issue, Thats why i was thinking it had something to do with the lock shield valve. It was open fully, but I've now changed it to almost fully closed.

My thinking was that if the valve was fully open then the hot water would drain away as soon as the heating was switched off.

Roddylarge

Pete67 wrote: »

You should have an energy meter installed in a house connected to a district heating system. The meter measures both supply and return temperatures, along with flowrate, and from this data it calculates the total heat energy consumed by the household in kWh. From a billing point of view, it does not matter what the supply and return temps are, the meter measures the actuals and calculates accordingly.

A temperature drop of 11C sounds about right. You should receive a bill from the operator of the district heating scheme showing the number of kWh consumed, along with details of the unit rate and any standing charges.

Thats exactly what we have Pete. I was just worried that i was paying for hot water that was being returned. Thanks for clarifying.