District Heating and Cooling

Nameless1 · 06-02-2008 02:29PM #1

Does anybody think district heating and cooling (for ex. 200 apartment block, one centralised boiler plant near the site heats all the apartments, therefore no boilers for each apartment, bolier can run on renewable or non-renewable sources), is worthwhile?
or has anybody any opinions on it?
thanks.

Mellor · 06-02-2008 03:02PM

I think it can be worthwile, a number of schemes have used or are using it,

The plants are often CHP units, (combined heat and power)

sydthebeat · 06-02-2008 03:04PM

They are absolutely worthwhile from the point of view of the occupier.
Economies are made in fuel prices by bulk delivery, fuel costs are based on usage alone and are paid on a metered basis so there is much more control over fuel costs.
These systems alone are very efficient, and if combined with a electricity producing source probably amasses to the future of sub-urban living.
http://www.sei.ie/index.asp?locID=1283&docID=-1

Mellor · 06-02-2008 03:26PM

sydthebeat wrote: »

These systems alone are very efficient, and if combined with a electricity producing source probably amasses to the future of sub-urban living.
http://www.sei.ie/index.asp?locID=1283&docID=-1

This is what was done in a housing development in the UK a few years ago, all the heat and elec for a estate is central. I can't see any downfall to it really.

Nameless1 · 06-02-2008 03:31PM

do you think it is worth while even if, say 200 apartments are insulated well above the requirements of the Regs and considering the relatively mild irish climate (realisticly it would probably be used 8-9 months in the year)?

as an investment could it be very poor then?

ChippingSodbury · 06-02-2008 03:41PM

The reason CHP plants become inefficient is if there isn't a relatively constant load: this is why it's good to get a diversity of users. In effect, this averages the demand which is a good thing for the unit. CHP becomes much more viable when gas turbines are used rather than IC engines. It's definitely a good idea for industrial uses where companies close to each other set up "communities" for their energy needs. Residential areas can then also tap in and buy their heat and power from the indsutrial community.
It's way more efficient than lots of mini boilers etc.

We should be trying to persuade the Greens to push this policy instead of wasting their time on the stupid Union Ward Hunt (no vested interest by the way!)

sydthebeat · 06-02-2008 03:47PM

Nameless1 wrote: »

do you think it is worth while even if, say 200 apartments are insulated well above the requirements of the Regs and considering the relatively mild irish climate (realisticly it would probably be used 8-9 months in the year)?

as an investment could it be very poor then?

without being smart, it would be worth it if you can retrieve its value in the sales of the apartments.
It would be a major selling point for the apartments. If you can construct them all as A rated, and show a probable energy requirement per year in KWhrs, you will be able to tell prospective purchasers out straight that it should cost them no more than X euros per year on heating and hot water at reasonable levels of usage. If their yearly heating costs was say €300-400 wouldnt that be a huge incentive.

You need to do the figures to see what you would have to sell the apartments at, in order to see its value.

And remember, 'energy efficiency' is not only about the engineering of buildings... it should be a philosophy and the whole project should be approached holistically from this view point.

Nameless1 · 06-02-2008 04:13PM

ChippingSodbury wrote: »

The reason CHP plants become inefficient is if there isn't a relatively constant load: this is why it's good to get a diversity of users. In effect, this averages the demand which is a good thing for the unit. CHP becomes much more viable when gas turbines are used rather than IC engines. It's definitely a good idea for industrial uses where companies close to each other set up "communities" for their energy needs. Residential areas can then also tap in and buy their heat and power from the indsutrial community.
It's way more efficient than lots of mini boilers etc.

We should be trying to persuade the Greens to push this policy instead of wasting their time on the stupid Union Ward Hunt (no vested interest by the way!)

the sei have a grant available for housing schemes that install a BIOMASS district heating scheme and obviously this will encourage its use and the majority of district heating schemes installed throughout ireland are biomass.
i have never heard of a CHP district heating scheme in ireland, maybe the big boys (sei,the greens) are hitting all the wrong notes.

CHP is an ideal option and i agree completly with you that maybe set it up for industry and then supply residential areas. far better to this than limit it to a few hundred apartments

my dissertation for college is on district heating and cooling and through my research, ireland is solving a problem by installing a district heating and/or cooling scheme (great for environment), but are we creating a problem in the future - biomass to expensive, not suitable to be expanded, limiting the use of other renewable sources by providing a grant for just biomass.

Mellor · 06-02-2008 05:09PM

Nameless1 wrote: »

CHP is an ideal option and i agree completly with you that maybe set it up for industry and then supply residential areas. far better to this than limit it to a few hundred apartments

The HSQ will have a district system, and it will supply the whole area, this will be mixed used between residential, commerial and retail

my dissertation for college is on district heating and cooling and through my research, ireland is solving a problem by installing a district heating and/or cooling scheme (great for environment), but are we creating a problem in the future - biomass to expensive, not suitable to be expanded, limiting the use of other renewable sources by providing a grant for just biomass.

Well cooling should be eliminated for a start. There is no need to have a cooling load if you are trying to be environmental, this is the worst use of energy in buildings.

Nameless1 · 06-02-2008 05:57PM

why would you eliminate cooling?
in the district heating and cooling process, cooling can be generated from sea water or waste heat from the scheme.
offices, shopping centres, among other buildings need cooling during the summer -what better way to use the heat you dont use?

Mellor · 07-02-2008 09:32AM

Cooling is the worst use of energy in a building. If you are aiming for a low energy building then cooling should, and can, be eliminated.

Heat you don't use???
Even if useing excess heat the same energy is wasted. It is far better to design with out a cooling load.

ardara1 · 07-02-2008 10:19AM

As far as I can work out, you will not be able to meet the LZC requirements or the 40% improvement without it - it's a necessity

Nameless1 · 07-02-2008 11:09AM

Mellor wrote: »

Cooling is the worst use of energy in a building. If you are aiming for a low energy building then cooling should, and can, be eliminated.

Heat you don't use???
Even if useing excess heat the same energy is wasted. It is far better to design with out a cooling load.

So how do you provide cooling? Just natural ventilation? Not really ideal, you can't say how much or how little you get. Natural ventilation you could say would suit apartments but most if not all commercial buildings need cooling, if you have a shopping center, shops will need cooling and many don't have windows

sydthebeat · 07-02-2008 11:12AM

ardara1 wrote: »

As far as I can work out, you will not be able to meet the LZC requirements or the 40% improvement without it - it's a necessity

are you saying that every apartment complex / residential complex requires DH or CHP to comply with the revised regs??? interesting....

Mellor · 07-02-2008 12:09PM

Natural ventilation is not ideal, are you serious??, its very much ideal. And where possible it should really be used. Zero energy cooling. I never said it was suitable for all buildings. Large shopping centres will of course need cooling, but then again they aren't as suited for district heating as they are large enough to warrent their own heat source (you could call this distrcit heating in the sense that it shares heating for all shopping units, but it is different to the thread topic as they are really a single unit)

But your suggestion that most commercial buildings need mechanicaly cooling is wrong. A number of offices buldings have been designed to be naturally ventilated.
Ventilation and glazing ratios are a huge factor in commercial office type buildings. They should be optimised. If cooling is then needed then so be it, but to planning a mechanical district cooling capable of dealing with the max load is bad imo. Or at least planning to use it is.

Nameless1 · 07-02-2008 02:03PM

Mellor wrote: »

Natural ventilation is not ideal, are you serious??, its very much ideal. And where possible it should really be used. Zero energy cooling. I never said it was suitable for all buildings. Large shopping centres will of course need cooling, but then again they aren't as suited for district heating as they are large enough to warrent their own heat source (you could call this distrcit heating in the sense that it shares heating for all shopping units, but it is different to the thread topic as they are really a single unit)

But your suggestion that most commercial buildings need mechanicaly cooling is wrong. A number of offices buldings have been designed to be naturally ventilated.
Ventilation and glazing ratios are a huge factor in commercial office type buildings. They should be optimised. If cooling is then needed then so be it, but to planning a mechanical district cooling capable of dealing with the max load is bad imo. Or at least planning to use it is.

I was saying that natural ventilation is not ideal in CERTAIN situations, i.e shopping centers. Of course it is ideal for many office blocks, apartments or whatever but not all.
District heating would work in a shopping center, there's no limit on what size of a building district heating can heat, the size of the plant that generates the heat may cause hassle but the one district heating scheme could heat as many different types of buildings as it wants, residential or commercial

Mellor · 07-02-2008 02:35PM

Nameless1 wrote: »

I was saying that natural ventilation is not ideal in CERTAIN situations, i.e shopping centers. Of course it is ideal for many office blocks, apartments or whatever but not all.

No thats not what you said. The post is just above so its easy to check.
You said its not ideal. And you have no way on knowing, this was before you mentioned building type.
Then you said most if not all commercial buildings will need cooling. Once again this is wrong, it can be design out, it often isn't which should change soon.

District heating would work in a shopping center, there's no limit on what size of a building district heating can heat, the size of the plant that generates the heat may cause hassle but the one district heating scheme could heat as many different types of buildings as it wants, residential or commercial

I never said it wouldn't work. I said that the shopping centre is large enough to run its own scheme. Due to the fact that when runs become longer there will be extra losses and the sheer size of a plant.
Shopping centres are rarely part of any sort other development. I don't consider "some" retail units as part of a mixed development a shopping centre. If these units did require cooling, it makes sense to have it stanf alone and provide adjoining residential or office units with natural ventilation

Nameless1 · 07-02-2008 03:09PM

Yea I take your point but many (not all) commercial buildings do need cooling whether that be natural ventialtion or from district cooling. If you have an office block using district heating and cooling, there will always be excess heat that won't be used (and in turn it will become cool) and one way of using this otherwise wasted air is to circulate it through the building as cool air.
Going back to your point saying "cooling is the worst use of energy in a building" that is wrong, regarding district heat and cooling is a very good option both technically and economically.
Yes, natural ventilation is a very good option but the forum is about district heating and cooling and cooling is the most economical option specific usually to a DHC plant only.
You can give your views on natural ventilation or cooling but you can't "eliminate" cooling if the correct system is in place (DHC)

Mellor · 07-02-2008 04:29PM

Nameless1 wrote: »

Yea I take your point but many (not all) commercial buildings do need cooling whether that be natural ventialtion or from district cooling. If you have an office block using district heating and cooling, there will always be excess heat that won't be used (and in turn it will become cool) and one way of using this otherwise wasted air is to circulate it through the building as cool air.

Can you explain what you mean by the hot air will become cool? And how it is a good use of energy.

Going back to your point saying "cooling is the worst use of energy in a building" that is wrong, regarding district heat and cooling is a very good option both technically and economically.
Yes, natural ventilation is a very good option but the forum is about district heating and cooling and cooling is the most economical option specific usually to a DHC plant only.

I'm sorry, but it is well established that cooling is a large user of energy. Energy that is easily not required. It is a bad use of energy.
Traditionally there are air handling units on the roof, these use alot of power, power that may not be required. DHC might reduce this power consumption to a better level, but there is still some sort of power used. Using natural ventilation, there is no power used, therefore no cooling load. Natural may not be fully possible but it will reduce it to a lower level.

You can give your views on natural ventilation or cooling but you can't "eliminate" cooling if the correct system is in place (DHC)

This is probably the weakest part of your argument.
Saying that a building still needs cooling, even its if natural, means that you can't eliminate it, is wrong. When people talk about eliminating heating or cooling thay are not refering eliminating the need for cooling but to eliminating a heating or cooling load.
Natural ventilation can fully eliminate a cooling load. Just like a passive house can eliminate a heating load.
Common sense will they you that the above buildings need to be heated and cooled respectivily. The passive house doesn't need to have a mechanical boiler to heat it but it is done passively. Through personnal or solar gains. This is technically heating, but there is no load, just as with natural ventilation.

I'm not saying that DHC units are bad, I was the first to say they were worthwhile. But saying they are the "most economical option" in terms of heating is not true.

Nameless1 · 07-02-2008 07:19PM

Mellor wrote: »

Can you explain what you mean by the hot air will become cool? And how it is a good use of energy.

I'm sorry, but it is well established that cooling is a large user of energy. Energy that is easily not required. It is a bad use of energy.
Traditionally there are air handling units on the roof, these use alot of power, power that may not be required. DHC might reduce this power consumption to a better level, but there is still some sort of power used. Using natural ventilation, there is no power used, therefore no cooling load. Natural may not be fully possible but it will reduce it to a lower level.

This is probably the weakest part of your argument.
Saying that a building still needs cooling, even its if natural, means that you can't eliminate it, is wrong. When people talk about eliminating heating or cooling thay are not refering eliminating the need for cooling but to eliminating a heating or cooling load.
Natural ventilation can fully eliminate a cooling load. Just like a passive house can eliminate a heating load.
Common sense will they you that the above buildings need to be heated and cooled respectivily. The passive house doesn't need to have a mechanical boiler to heat it but it is done passively. Through personnal or solar gains. This is technically heating, but there is no load, just as with natural ventilation.

I'm not saying that DHC units are bad, I was the first to say they were worthwhile. But saying they are the "most economical option" in terms of heating is not true.

A DHC schemes generates a certain load of heat to users, users may not always use every bit of this heat, therefore over time this heat cools down to a level that is acceptable to be used as cooling air, this gets the best of both worlds - good use of energy.

I agree that DC will use some sort of power but if your heating several buildings all heat will not be used so therefore reuse it as cool air. Countries like Denmark, Austria, Finland, etc have been making millions from this technology and reducing their CO2 emissions, proving it is both a very good financial and energy efficient option.

Sorry, maybe I should make the messages more clear. I agree with natural ventialtion and passive heating but DHC has proven to be very beneficial to users, management companies, the comunity, the environment, etc, as with the other two. Yea it as a "load" but on large scale schemes they are extremely economical, and can benefit a lot more people among other things.

I agree but if the schemes are large enough and maintained correctly they can work wonders

Nameless1 · 07-02-2008 07:20PM

Sorry that message came up very bad, my parts are mixed up in your parts mellor

sinnerboy · 07-02-2008 09:19PM

Tangential point point here .... Last week I gave a committee of 12 apartment owners the bad news on the condition of therir 25 year old roof . needs repairs . a lot . a ( rhetorical , really ) question was asked "how could we let it get this bad ? " and why didn't "somebody " do "something" to prevent the "neglect ".

Now I know well run management regimes SHOULD levy contingency sums but I believe few DO .

I think human nature is to regard things in joint ownership as not really being "owned" at all - by that I mean people don't feel inclined toward a sense of responsibility for the shared item - in this case a roof , ......until they start to get wet .

The agent was grilled as to why no contingecy sum was levied - he reminded them that every ( badly attended ) prior residents committee down the years elected to keep maintenance costs to the bone - communal area lighting , decoration , refuse collections , etc - end of !

I think it is probably fair to say that apartment dwellers see themselves moved on in 15/20 years time and so will not feel inclined to contribute towards eventually significant refurb works , whch they believe they will not benefit from .

Now I am not knocking CHP here ( any more that I am knocking roofs

)

But substitute "CHP unit" for "roof" in my tale .........

Nameless1 · 08-02-2008 11:12AM

sinnerboy wrote: »

Tangential point point here .... Last week I gave a committee of 12 apartment owners the bad news on the condition of therir 25 year old roof . needs repairs . a lot . a ( rhetorical , really ) question was asked "how could we let it get this bad ? " and why didn't "somebody " do "something" to prevent the "neglect ".

Now I know well run management regimes SHOULD levy contingency sums but I believe few DO .

I think human nature is to regard things in joint ownership as not really being "owned" at all - by that I mean people don't feel inclined toward a sense of responsibility for the shared item - in this case a roof , ......until they start to get wet .

The agent was grilled as to why no contingecy sum was levied - he reminded them that every ( badly attended ) prior residents committee down the years elected to keep maintenance costs to the bone - communal area lighting , decoration , refuse collections , etc - end of !

I think it is probably fair to say that apartment dwellers see themselves moved on in 15/20 years time and so will not feel inclined to contribute towards eventually significant refurb works , whch they believe they will not benefit from .

Now I am not knocking CHP here ( any more that I am knocking roofs )

But substitute "CHP unit" for "roof" in my tale .........

Fair point. But in my opinion there is no comparasion. If a CHP plant is used, all consumers have to do is use the heat and power and pay their monthly subscription.

A management company in charge of the plant invests money (from these monthly subscriptions) into the plant to maintain it in such way that it never gets to level that it becomes unusable.

The management company is there to make a profit and they will make sure that the plant continues making money rather than losing it.

Nameless1 · 08-02-2008 11:30AM

Regarding what you where saying Mellor, yes people might start saying "sure the DH will do it", could be a problem, where people will become over reliant on a system but DHC and natural ventilation have there benefits, although some may be different, I definatly don't think that will happen were people will become over reliant, DHC will only be a small sector in Ireland, it doesn't appeal to existing buildings and is idealy suited to new developemts, whereas natural ventialtion suits existing and new buildings.

I think the County Hall in Cork did this, refurbished the entire building and incorporated natural ventilation.

sinnerboy · 08-02-2008 06:56PM

Nameless1 wrote: »

Fair point. But in my opinion there is no comparasion. If a CHP plant is used, all consumers have to do is use the heat and power and pay their monthly subscription.

A management company in charge of the plant invests money (from these monthly subscriptions) into the plant to maintain it in such way that it never gets to level that it becomes unusable.

The management company is there to make a profit and they will make sure that the plant continues making money rather than losing it.

Point is , these subs are always considered too high . They are scrutinised and paired to the bone . You are describing what SHOULD happen . My tale is about what DOES happen .....

Other than that , CHP - thumbs up

Nameless1 · 09-02-2008 09:30AM

sinnerboy wrote: »

Point is , these subs are always considered too high . They are scrutinised and paired to the bone . You are describing what SHOULD happen . My tale is about what DOES happen .....

Other than that , CHP - thumbs up

Yea thumbs up to CHP, if thats what does happen, it may improve in years to come, as we know CHP is a relatively small market in this country, maybe people in charge of these plants might change this when the market grows, they own more - they make more money - possibly prices/costs may be reduced.

09-02-2008 02:44PM

Talking about CHP, does anyone know of any "live" (single dwelling) micro-CHP systems in use in Ireland(or Europe)?

Nameless1 · 11-02-2008 03:26PM

Deleted User wrote: »

Talking about CHP, does anyone know of any "live" (single dwelling) micro-CHP systems in use in Ireland(or Europe)?

I don't think it has really started in Ireland yet, it has been mentioned in England but don't think there are any "live" systems. It is referred to as dCHP (Domestic Combined Heat and Power).

And current research has suggested it may work out more costly than conventional heating systems

Mellor · 11-02-2008 04:35PM

I know of some houses running CHP in the UK, but it is split between a small group not a single unit

District Heating and Cooling

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