Half a croissant, on a plate, with a sign in front of it saying '50c'
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Energy efficient apartment blocks

economies of scale: centralize EVERYTHING
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Hi All - my first post so feel free to haze me as much as you like.

And I know this has been done to death already.

When I look over from my hotel to the building next to me, I see dozens of air conditioner compressor units staring back. I expect that each of those apartments also has a dedicated fridge or three, a heater (though not necessarily here in Singapore) and more rarely, its own hot water system as well.

All those hundreds of little motors driving little refrigerant loops, throwing away energy through frictional losses and whatnot. And I've always wondered how much heat a refrigerator emits into the home...

These losses could be drastically reduced by centralizing almost all the building's systems. I know that most modern building have centralized HVAC and hot water, but what if the refrigeration, heating, cooling, hot water and lighting could all be powered from a central control area situated in the basement, but controlled by each apartment's user to suit their own preferences.

The use of double-glazing and good insulation would ensure minimal energy usage to maintain room temperature.

The lighting would be an array of several powerful sulfur lamps which can be switched on or off to compensate for load, but ideally can provide more than enough light for the entire building. The situation of these in the basement would be advantageous for cooling but also in that they could easily be enclosed in a faraday cage to prevent interference in the 2.4GHz band. Light would be delivered by fibre-optic cables, and 3M's 'light pipes' would be used for room illumination. A 'light valve' would be necessary to achieve the desired amount of lighting. It would consist of two circular polarizing filters superimposed flat up against each other, with one stationary and one free to rotate and connected in some manner to a dimmer type switch. The orientation of each light valve would be reported back to the control system so that sulfur lamps could be switched on and off as necessary. Skylights and fibre-optics could be used to provide daytime lighting.

A chilled water system would provide 'cold' for refrigerators and air conditioning. Refrigerators and air blowers in each room would have inside them heat exchangers over which air would pass. The chilled water would flow through the heat exchangers into a return loop. Temperature control is done via a ball valve restricting water flow through the heat exchangers. The valve would be controlled via a digital interface attached to a touch screen or similar [voice command?].

The central heating system would be part of the hot water system, and have its own set of heat exchangers in the air blowers.

The hot and cold (chilled) water systems would be looped and constantly circulating such that the operation of any device would have a negligible effect on the availability of working fluid to any other device.

It may be possible to use the waste heat from the chiller system to feed into the hot water system.

The only problem that comes to mind is the light valve - using polarized filters would reduce efficiency by 50%. Perhaps there is a material whose reflectivity can be varied...

SeeJayDee, Feb 02 2010

Single_20Source_20House_20Lighting [FlyingToaster, Feb 03 2010]

Solar_20Lighting [FlyingToaster, Feb 03 2010]

[link]






       I like the idea of refrigeration heat being used to help out with heating and there are probably lots of other tradeoffs like this that could be done.   

       My suspicion that this idea is probably describing an existing style of thermal engineering that probably has its own term.   

       Welcome to the Halfbakery - we only expect ideas to be original, thought-provoking, practical and surreal so not too much pressure, eh?
Aristotle, Feb 02 2010
  

       I like the fridge idea just because it would be quieter than having a refrigerator running in one's own apartment. [+]
gisho, Feb 02 2010
  

       The most original idea in this is central refrigeration, which is interesting, but unless you could standardize refrigerator placement, probably a net loss due to piping losses. Centralized water heating has the same issue which is why lots of little tankless water heaters are becoming popular in new homes.   

       The central lighting probably wouldn't beat LED lighting, unless you swap the Sulfer lamps with a roof mounted parabolic solar collector. This is baked and a good idea as long as you can keep the losses of the light piping down and filter out the IR unless it is desired for heating.   

       Welcome to the HB. I will offer a "welcome" bun but will expect more from future offerings.
MisterQED, Feb 02 2010
  

       What heat transfer fluid do you propose to have in the pipes which connect individual food cooling boxes to the central refrigeration device?   

       Furthermore, do you propose two loops, one for "cool" and one for "freezing", or one loop?
goldbb, Feb 02 2010
  

       if you have a freezing loop you may as well use it for a cool loop.   

       Glycol/water works quite nicely down to -50 or so.
FlyingToaster, Feb 02 2010
  

       You raise a good point with your 'two loops' idea, goldbb. A chilled water loop wouldn't be able to provide sub-zero cooling for obvious reasons. I had wanted to avoid piping refrigerants up into the building for safety/environmental reasons. I suppose, since CO2 can be used as a refrigerant, that it would be acceptable to use. This would also remove the need to chill water in a tank, potentially boosting efficiency. Perhaps an odorant could be added to the gas to detect leaks. This would be a single loop attached to the fridges and aircons of the buildings.   

       Edit: FlyingToaster I like your idea of water/glycol, as there is no danger of asphyxiation if a leak occurs. Even though Eth-glycol is toxic, it is a liquid and can be seen and avoided if spilled.   

       MisterQED, I wanted to avoid LEDs because they are difficult to recycle and last time I checked sulfur lamps were a couple of percentage points more efficient than LEDs. Also, a single array of 20 or so sulfur lamps in one place would be easier to maintain than thousands of LEDs throughout the building, although LEDs could potentially be used for supplementary/spot lighting.   

       I like the idea of a parabolic solar collector on the roof. I believe there are technologies to filter out IR (I know they can filter UV - perhaps same principle). This could be used as a hybrid system also feeding into the main light piping system, for daytime lighting.   

       Thanks everybody for your input :)
SeeJayDee, Feb 02 2010
  

       //glycol// IIRC the downside is the more the glycol in the mixutre, the lower the specific heat.   

       But wait ! ... there's more !!! Act now and read a couple more posts <links> (hey, a newb croissant is still crunchy)   

       You can divide out portions of the sunlight too: always use the stuff outside of visible-light for heating when needed or electricity, and the viewable light gets used for lighting when needed, or heating/electricity when not. May want to toss in a greenhouse too and separate out the chlorophyll-absorption spectra while you're at it.
FlyingToaster, Feb 03 2010
  
      
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