Nearly 1,000 households in Tengah sign up for centralised cooling system

[Kklee]

27 minutes ago, Ct3833 said:

Thanks for the video illustration. I am still skeptical because am not educated enough about how these system work. In some office buildings or even shopping centers, one may notice that those units at the far end are hot and stuffy,  likewise those facing the west sun are having hotter aircon environment than those facing the cooling areas. I could be wrong. While the cooling system feeds the water around the building,  there would be heat heat loss when the cold water move from one end to another, by the time the water gets to the last unit, it will be unrealistic to expect the water temperature to be as cold as that when it was fed to the first room. <--- The water temperature is strictly managed including how much "cold" can be removed per HDB unit i.e. a HDB unit cannot remove so much "cold" (in total) that it causes the effect that you described. 

Next scenario, if a user prefers to have 23 degree, and the other room likes to have 26 degree , how could this be achieved? i know it will likely be controlled by airflow since the temperature cannot be changed, that would mean the one who wants to have higher   temperature cannot turn on higher air flow ? and the one who needs lower temperature have to tune up his blower at night?   And if one unit prefers to have very cool air(in a extreme manner say 23 or 34 degree C) ,  likely that unit will have to be very disappointed since the supplied temperature is constant. I could be wrong.  <-  The individual FCU ( in the different room ) is temperature controlled just like a normal AC.   Different room's FCU's temperature can be individually set.  When the temperature reaches the setting,   the FCU will slow down or switch off.  

Based on my readings off the internet.   Above in red. 

[Yewheng]

Really feel that what government is doing is just being kay kiang.. Coz for commercial building all building will have aircon and just leave it that way. However for residential homes, not all households will want to use aircon maybe due to want save electricity bills, or some use only a few hours each day. So how to justify for these people? So it is opt in.. Then what if the demand is not high and the central chiller system still need to run 24/7 anyway, plus maintenance. Like that how to spread out the cost and yet affordable to each households who opt in? The current air con unit that is ownself install is okay ma. Want aircon just go shop for aircon and then pay for it and install, if don't want aircon then no need even spend a single cent on aircon ma.. So what's the fuss about it? 

Edited October 21, 2020 by Yewheng

[Kklee]

1 minute ago, Yewheng said:

Really feel that what government is doing is just being kay kiang.. Coz for commercial building all building will have aircon and just leave it that way. However for residential homes, not all households will want to use aircon maybe due to want save electricity bills, or some use only a few hours each day. So how to justify for these people? So it is opt in.. Then what if the demand is not high and the central chiller system still need to run 24/7 anyway, plus maintenance. Like that how to spread out the cost and yet affordable to each households who opt in? The current air unit that is ownself install is okay ma. Want aircon just go shop for aircon and then pay for it and install, if don't want aircon then no need even spend a single cent on aircon ma.. So what's the fuss about it? 

IMHO,  you can say the government is being kay kiang now,  until the day someone use carbon footprint against the country. 
Anyway, I see the implementation is really about solar energy. 

[Yewheng]

Just now, Kklee said:

IMHO,  you can say the government is being kay kiang now,  until the day someone use carbon footprint against the country. 
Anyway, I see the implementation is really about solar energy. 

Darn it.. If really want to talk about carbon footprint.. It should be in the case of really can save money and not end up become more expensive in long run.. Like hidden cost of maintenance... 

[Kklee]

1 minute ago, Yewheng said:

Darn it.. If really want to talk about carbon footprint.. It should be in the case of really can save money and not end up become more expensive in long run.. Like hidden cost of maintenance... 

IMHO.
If don't use,  it will cost less.  If use alternative,  it may cost more.

E.g.   
Like for example printing on laser printers.
Using recycled A4 paper is different from recycling / reuse the A4 paper that the back is empty.
Sure you can use the empty back of a used A4 paper for printing,   the printer will be extremely dirty and require more maintenance. 

 

[Stratovarius]

18 hours ago, Voodooman said:

Based on my reading, there won't be one cooling tower in each block. In Marina Bay area, they have 3 plants that covers the whole of MBS, MBFC, etc.  This only works if there is scale.

Ok. If there is an aircon ledge, then just piped the main DC pipe to the aircon ledge area. If it is no longer economical, just disconnect and buy a few compressors to take over. Should be able to use the same piping to the fancoil, i presume. Why need to run new pipes.  Sorry, i am a noob on such matters, just trying to learn something here. 

From the article in the 1st post:

"Under the CCS, chilled water will be piped to homes from centralised chillers installed on the rooftops of selected Housing Board (HDB) blocks. This is more energy-efficient compared with conventional air-conditioning systems, said SP Group."

 

[Victor68]

2 hours ago, Ysc3 said:

Just have to wait for hdb to say how they bill.

For me, the bill is most important.

Hope I am not 'pouring cold water' on this idea. It is not workable and high maintenance cost in the long run. Whoever came up with this gimmick will make money and run. Like the vacuum refuse system for HDB. Haha

[13177]

14 minutes ago, Victor68 said:

Hope I am not 'pouring cold water' on this idea. It is not workable and high maintenance cost in the long run. Whoever came up with this gimmick will make money and run. Like the vacuum refuse system for HDB. Haha

The vacuum refuse system heard before, so now this system has been axe liao?

[Stratovarius]

1 hour ago, Ct3833 said:

Thanks for the video illustration. I am still skeptical because am not educated enough about how these system work. In some office buildings or even shopping centers, one may notice that those units at the far end are hot and stuffy,  likewise those facing the west sun are having hotter aircon environment than those facing the cooling areas. I could be wrong. While the cooling system feeds the water around the building,  there would be heat heat loss when the cold water move from one end to another, by the time the water gets to the last unit, it will be unrealistic to expect the water temperature to be as cold as that when it was fed to the first room.

Next scenario, if a user prefers to have 23 degree, and the other room likes to have 26 degree , how could this be achieved? i know it will likely be controlled by airflow since the temperature cannot be changed, that would mean the one who wants to have higher   temperature cannot turn on higher air flow ? and the one who needs lower temperature have to tune up his blower at night?   And if one unit prefers to have very cool air(in a extreme manner say 23 or 34 degree C) ,  likely that unit will have to be very disappointed since the supplied temperature is constant. I could be wrong.

The system that HDB is setting up is different from your commercial building. What they are doing is using chill water to replace the need for the AC compressor. Temperature control is still by the individual FCU. Chill water temp can be as low as 3 degree C while Ac setting lowest is around 17. So i dont see that as an issue. 

As for commercial buildings, the chill water is feed to a AHU. These are like big a** FCU that feeds cold air to large areas via air ducts. It's impossible to balance temperature in big areas due to different local heat loads. Thats why you feel some area is colder than other. As for the 2nd scenario, different setting can be met by using different AHU or if it's a small office or meeting room, installing a FCU to regulate the temperature will resolve the problem. 

[Watwheels]

1 hour ago, Ct3833 said:

Thanks for the video illustration. I am still skeptical because am not educated enough about how these system work. In some office buildings or even shopping centers, one may notice that those units at the far end are hot and stuffy,  likewise those facing the west sun are having hotter aircon environment than those facing the cooling areas. I could be wrong. While the cooling system feeds the water around the building,  there would be heat heat loss when the cold water move from one end to another, by the time the water gets to the last unit, it will be unrealistic to expect the water temperature to be as cold as that when it was fed to the first room.

Next scenario, if a user prefers to have 23 degree, and the other room likes to have 26 degree , how could this be achieved? i know it will likely be controlled by airflow since the temperature cannot be changed, that would mean the one who wants to have higher   temperature cannot turn on higher air flow ? and the one who needs lower temperature have to tune up his blower at night?   And if one unit prefers to have very cool air(in a extreme manner say 23 or 34 degree C) ,  likely that unit will have to be very disappointed since the supplied temperature is constant. I could be wrong.

It's just like your car. If the sun is directly over your car it will be hot regardless how the aircon is working. That's why ppl install window tint.

But for home or office they are able to install double glazing windows to minimise the heat from the sun.

For commercial buildings there are ways to make the distribution of cool air even in a large area. For residences there's no need to. If you find any corner that's not cool in your home simply put a small fan in the corner. Its purpose is to draw the cool air over to that corner. So as to make the cool air distribution more even. For commercial building engineers use a RAG or return air grill and they can use multiple of such grills. It's a duct to draw air via a small fan (hidden behind the grill so it can't be seen) and return the air to the main system. Much like what I mentioned a small will help in a home setting.

Anyway the system has been perfected over many years. The aircon central system is usually reliable. 

 

[Ysc3]

1 hour ago, Victor68 said:

Hope I am not 'pouring cold water' on this idea. It is not workable and high maintenance cost in the long run. Whoever came up with this gimmick will make money and run. Like the vacuum refuse system for HDB. Haha

The vacuum refuse thing up and running already? 

I rem a few years back,  a surveyor came to my house at night to ask questions about this.... But the surveyor stand outside lah ... Lasted almost 10 mins !

[Voodooman]

3 hours ago, Stratovarius said:

From the article in the 1st post:

"Under the CCS, chilled water will be piped to homes from centralised chillers installed on the rooftops of selected Housing Board (HDB) blocks. This is more energy-efficient compared with conventional air-conditioning systems, said SP Group."

 

Thanks. Do you know what is the difference between chillers and main DC plant? I googled but still confused.

[Voodooman]

2 hours ago, Victor68 said:

Hope I am not 'pouring cold water' on this idea. It is not workable and high maintenance cost in the long run. Whoever came up with this gimmick will make money and run. Like the vacuum refuse system for HDB. Haha

Interesting article. This DC set up is apparently quite common in the Middle East. The science is proven but it really depends on the charges. Read there is a capacity charge and a usage charge for the SP scheme in Tengah.

https://gulfnews.com/business/analysis/why-is-there-so-much-consumer-heat-over-district-cooling-1.1279161

 

[Stratovarius]

33 minutes ago, Voodooman said:

Thanks. Do you know what is the difference between chillers and main DC plant? I googled but still confused.

If we talk about commerical buildings, in terms of function, it's the same. What dc does is to consolidate multiple systems in different buildings into one. One of the benefits I can think of is reducing redundancy system. You always need a redundancy system for acmv. So if there are 5 buildings, you need 10 systems. But for dc, you only need 2. Other cost savings like monitoring system and manpower can be reduced. Just my 2c.i may not be right. 😁😊

[Stratovarius]

35 minutes ago, Voodooman said:

Thanks. Do you know what is the difference between chillers and main DC plant? I googled but still confused.

Double post

Edited October 21, 2020 by Stratovarius

[Kb27]

I read some other remarks:

1. Maintenance cost is more or less fixed and likely to rise in the future. If SP offers you $X bill today with 1,000 household, what happens when the number of household drops for some reasons ? Will they increase your bill ? Probably, quite likely, then more household drops, cascading effect.

2. As the plant gets older more parts need to be replaced, again will SP  offload the bill onto consumers ?

They can talk all about efficiency, but the final sticking point is how much $ you pay ?

And when it's time you decide to remove that white elephant hanging off your wall, you have to pay $400.

[Victor68]

19 minutes ago, Voodooman said:

Interesting article. This DC set up is apparently quite common in the Middle East. The science is proven but it really depends on the charges. Read there is a capacity charge and a usage charge for the SP scheme in Tengah.

https://gulfnews.com/business/analysis/why-is-there-so-much-consumer-heat-over-district-cooling-1.1279161

 

 basic air-conditioning knowledge tell you the efficiency of the central chiller plant at constant load of 90% would yield the best result. When you run a pipe work from Jurong to serve changi and changi decides only need 20% load for certain timing, you either impose penalties or suffer losses. This is not much difference from Singapore power trying to attract night load to CBD. Electricity is easier to manage than chilled water for long distance. My 2-cent on the subject.

[Voodooman]

3 hours ago, Victor68 said:

 basic air-conditioning knowledge tell you the efficiency of the central chiller plant at constant load of 90% would yield the best result. When you run a pipe work from Jurong to serve changi and changi decides only need 20% load for certain timing, you either impose penalties or suffer losses. This is not much difference from Singapore power trying to attract night load to CBD. Electricity is easier to manage than chilled water for long distance. My 2-cent on the subject.

You can't use thermostat to auto switch on and off (or run at lower load) like a home fridge (like Honda Vtec) when water temperature is at an optimal level with reduced usage? 

I am not sure if transmission loss for electricity is easier to manage than a DC system, which is dependent on pipe insulation to minimize cooling loss. Our power plants are mostly located all over the island but DC plants are built at location, so distance traveled would be far shorter.  Happy to hear your expert opinion.