Can we treat the governments policies on saving energy seriously?

cepheus

Nearly every shop door on my High Street was wide open yesterday, allowing heat directly out of the front entrance. To make matters worse some of these shops have electric fan heaters directly above the entrances, so not only is much of this heat wasted, it is generated in the most, expensive and carbon intensive manner possible.

There reason is surely obvious, the owners perceive that the profits gained from encouraging more customers into the shop by opening doors outweighs any energy saving from closing the doors.

However, doesn't this make a mockery of insulation measures, even more so the expensive cost ineffective schemes which are heavily subsidised by the taxpayer such as private micro-generation? Surely we need to have a pecking order for cutting energy. We start with the most cost effective measures first with everybody shutting the bloody doors, then insulation then large wind turbines and leave photovoltaics near to the end!

whasup

Am I reading that right; you are saying you think large wind turbines are the most cost effective just after insulation?

cepheus

Wind turbines are more expensive than insulation (which save money) but far cheaper than domestic solar in the UK. There are far more measures than that though!

There are vast differences in wind costs between on shore and off shore, commercial and micro, and low penetration and high penetration. The former are cheap the latter expensive in each case.

This is the full abatement curve for CO2. I don't think solar is even on the chart for UK conditions, it is ruinously expensive on a social level!

albyota

its even worse in nurseries, infant, junior and primary schools with their open door policy at play times, as the kids are not to be restricted from going in and out, so the doors are just left open...all the heat from the building escapes, and the tax payer foots the bill.

whasup

That's ok. I thought you were saying that wind energy is third on the scale of cost efficient measures, when they are really at opposite ends of the scale. I used to be buildings manager (surveyor) for (what was then) the largest retail group in the UK. Thousands and thousands of high street outlets. I can tell you that the biggest problem is cooling - not heating. Even in the dead of winter a lot of heat pumps are on reverse. (i.e. cooling not heating) The reason is simple; people, lighting and solar gain. Shops can get very hot with no heating at all. Normally it wouldn't be permitted to open doors because the immediate zone inside a shop is THE most important and they wouldn't want cold spots. But on a cool but fairly mild day - like we've had recently - it would be reasonable to open doors and let a bit of unwanted heat out rather than turn on the cooling. Also bear in mind that all that heating and cooling is by heat pump so uses nothing like the sort of energy a home system uses.

zeupater

cepheus wrote: »

Nearly every shop door on my High Street was wide open yesterday, allowing heat directly out of the front entrance. To make matters worse some of these shops have electric fan heaters directly above the entrances, so not only is much of this heat wasted, it is generated in the most, expensive and carbon intensive manner possible.

There reason is surely obvious, the owners perceive that the profits gained from encouraging more customers into the shop by opening doors outweighs any energy saving from closing the doors.

However, doesn't this make a mockery of insulation measures, even more so the expensive cost ineffective schemes which are heavily subsidised by the taxpayer such as private micro-generation? Surely we need to have a pecking order for cutting energy. We start with the most cost effective measures first with everybody shutting the bloody doors, then insulation then large wind turbines and leave photovoltaics near to the end!

Hi

The blowers above the door should not be there to provide heat, but to form an air curtain to minimise the exchange of warmer/cooler air within the store with the ambient condition outside and as such provide an overall energy saving to premises where large entrance doors exist .

Info ... http://en.wikipedia.org/wiki/Air_door

HTH
Z

cepheus

whasup wrote: »

That's ok. I thought you were saying that wind energy is third on the scale of cost efficient measures, when they are really at opposite ends of the scale. I used to be buildings manager (surveyor) for (what was then) the largest retail group in the UK. Thousands and thousands of high street outlets. I can tell you that the biggest problem is cooling - not heating. Even in the dead of winter a lot of heat pumps are on reverse. (i.e. cooling not heating) The reason is simple; people, lighting and solar gain. Shops can get very hot with no heating at all. Normally it wouldn't be permitted to open doors because the immediate zone inside a shop is THE most important and they wouldn't want cold spots. But on a cool but fairly mild day - like we've had recently - it would be reasonable to open doors and let a bit of unwanted heat out rather than turn on the cooling. Also bear in mind that all that heating and cooling is by heat pump so uses nothing like the sort of energy a home system uses.

That doesn't excuse it. I was passing the shops in the morning when it was cold and foggy, and it was an electric fan heater on inside the shop but over the open door.

Any excess heat caused by necessary electrics and body heat should be ventilated out, whilst blinds should be used to reflect solar gain. It should not normally be necessary for air conditioning in winter unless it is literally jam packed.

cepheus

zeupater wrote: »

Hi

The blowers above the door should not be there to provide heat, but to form an air curtain to minimise the exchange of warmer/cooler air within the store with the ambient condition outside and as such provide an overall energy saving to premises where large entrance doors exist .

Info ... http://en.wikipedia.org/wiki/Air_door

HTH
Z

Thanks for this, it seems unlikely this would work better than a closed door and indeed it suggests this within the wiki article.

Air curtains can be used to save energy by reducing the heat transfer (via mass transfer when air mixes across the threshold) between two spaces, although a closed and well-sealed physical door is much more effective

In fact I am amazed it doesn't waste more heat blowing hot air across a door. I remain sceptical.

This campaign is interesting though. Obviously it isn't only me which has realised this, and of course most retailers have completely ignored it!

http://en.wikipedia.org/wiki/Close_the_Door_campaign

I notice some supermarkets use a revolving door which might work better in windy conditions, although I'm not sure otherwise.

zeupater

cepheus wrote: »

Thanks for this, it seems unlikely this would work better than a closed door and indeed it suggests this within the wiki article.



In fact I am amazed it doesn't waste more heat blowing hot air across a door. I remain sceptical.

This campaign is interesting though. Obviously it isn't only me which has realised this, and of course most retailers have completely ignored it!

http://en.wikipedia.org/wiki/Close_the_Door_campaign

I notice some supermarkets use a revolving door which might work better in windy conditions, although I'm not sure otherwise.

Hi

I agree that closing the door is better, but in many situations this becomes impractical. For example, in many warehouse type environments where there are large numbers of movements of personnel and fork-lift trucks between the inside and outside of a building air-curtains are very popular and actually do reduce the space heating requirements.

I have worked in/with sites where automated doors have been ripped out due to the reaction time of the mechanism to be replaced by air-curtains and have seen the financial justification and actual resultant cost savings and therefore believe that they can actually provide savings ... I suppose that in retail it all comes down to footfall - if the footfall is high automated doors would spend most of their time open anyway, therefore an air-curtain makes sense whereas on lower footfall automated doors would remain closed longer and make more sense ....

HTH
Z

cepheus

If is does work, there is no reason you couldn't have both, were the air comes on when the door is open. Modern opening doors are very quick.

zeupater

cepheus wrote: »

If is does work, there is no reason you couldn't have both, were the air comes on when the door is open. Modern opening doors are very quick.

Hi

There are many places which have both automated doors and air curtains which are used depending on how busy the doorway is at a particular time and which season it is ....

In the case of a warehouse/factory external door, many of these are somewhere around 5m wide and at least as high and even the fastest operating automated roller doors are slow and need large 'safety zones' to prevent a closing door from causing injury and plastic strip curtains usually create line-of-sight safety issues, therefore air-curtains are used.

I do follow your thoughts on the relative performance efficiencies of doors vs air-curtains and agree .... but it's very likely that someone at the head-office of the stores which keep the doors open has calculated the benefit of the open doors encouraging passing trade to enter the store against the extra cost of heating and decided that air-curtains are the best compromise available ....

One issue which is probably more relevant to energy saving in many shops/stores is the fact that the majority of shop-fronts are single glazed and there is still a high reliance on the use of halogen spotlighting to provide retail display emphasis, these both being the case whether the store has doors or air-curtains .... I recently went into a bank branch which had a framed certificate on the wall stating the bank's energy efficiency policy, that the branch had been audited for compliance and had scored well - what made me laugh was that the certificate was highlighed by a standard halogen light after which I noticed that there were absolutely hundreds of halogen downlights in the banking hall and not one LED unit - so much for the audit process ...

HTH
Z