Results 1 to 26 of 26
-
14-10-2008, 11:24 AM #1
Air conditioning energy consumption
Hi all,
I'm currently working on the development of a new hybrid ventilation system that has the ability to warm and cool incoming supply air.
Now we want to compare the energy use of the system with that of a 'through the wall' packaged air conditioner. We're using CIBSE weather data that gives an hour-by-hour account of a typical year. I've worked out how much energy our system will use, but am struggling to find any data on how much energy an equivalent a/c system would consume.
Any ideas?
Thanks in advance!
-
14-10-2008, 01:20 PM #2
Re: Air conditioning energy consumption
Hi,
Can details be provided on method by which air is being cooled / warmed.
RegardsVijay Kumar
HVAC Design Engineer
BMCPL
"The more you sweat in peace less you bleed in war"
-
14-10-2008, 02:59 PM #3
Re: Air conditioning energy consumption
Our system simply circulates hot or cold water through a heat exchanging copper coil. The air passes over the coil and then into the room.
We 'd like to compare to a compressor-based refrigerant system of around 1kW.
-
14-10-2008, 03:32 PM #4
Re: Air conditioning energy consumption
A bit more detail:
Over the period of one year our unit will use 57kWh to maintain a supply air temperature of 20C at 40l/s over the summer (i.e. when ambient temperature is above 20C).
Over the winter the unit will require 780kWh to supply air at 18C, again at 40l/s whenever ambient temperature drops below 18C.
-
14-10-2008, 03:43 PM #5
- Join Date
- Sep 2007
- Location
- Split Croatia
- Age
- 57
- Posts
- 6,151
- Blog Entries
- 6
- Rep Power
- 36
Re: Air conditioning energy consumption
Energy consumption can be compared only by comparing COP for different weather conditions of your system and given "window shaker".
-
14-10-2008, 11:08 PM #6
Re: Air conditioning energy consumption
I think you should also be aware that you are trying to compare two completely different systems.
You are designing a ventilation system
but you are doing a cost comparison with an air recirculation system.Brian - Newton Abbot, Devon, UK
Retired March 2015
-
28-10-2008, 02:29 PM #7
Re: Air conditioning energy consumption
Yes I realised this! My problem is that I work under two supervisors- an academic supervisor who told me that you can't compare the two systems, and an industry supervisor who wants me to compare them nevertheless!
Some might say that I'm stuck between a rock and a hard place.
-
13-11-2008, 11:33 AM #8
Re: Air conditioning energy consumption
Any idea how converting a through the wall air conditioner to use fresh air would affect the COP? I think what I'm being asked to do is not possible
-
13-11-2008, 11:46 AM #9
- Join Date
- Sep 2007
- Location
- Split Croatia
- Age
- 57
- Posts
- 6,151
- Blog Entries
- 6
- Rep Power
- 36
-
13-11-2008, 11:59 AM #10
Re: Air conditioning energy consumption
-
13-11-2008, 12:17 PM #11
- Join Date
- Sep 2007
- Location
- Split Croatia
- Age
- 57
- Posts
- 6,151
- Blog Entries
- 6
- Rep Power
- 36
Re: Air conditioning energy consumption
Why 100%?
Any idea where I can find typical COPs for these window shakers? Manufacturer's literature is extremely vague!
Maybe Eurovent site.
I am sure that you could always send e-mail to manufacturer for that data!
-
13-11-2008, 02:42 PM #12
Re: Air conditioning energy consumption
-
13-11-2008, 03:02 PM #13
-
13-11-2008, 03:04 PM #14
Re: Air conditioning energy consumption
I'm looking at a ventilation unit that uses 100% fresh air, and then trying to compare it to a different sort of unit to see if it offers any advantages from an energy point of view.
Basically trying to find a way to justify the development of the new unit. Which is quite hard!
edit: That eurovent site is brilliant- thanks!Last edited by wilsonudevil; 13-11-2008 at 03:08 PM.
-
13-11-2008, 03:11 PM #15
Re: Air conditioning energy consumption
Last edited by Gary; 13-11-2008 at 03:21 PM.
-
13-11-2008, 03:49 PM #16
- Join Date
- Sep 2007
- Location
- Split Croatia
- Age
- 57
- Posts
- 6,151
- Blog Entries
- 6
- Rep Power
- 36
-
13-11-2008, 06:38 PM #17
Re: Air conditioning energy consumption
@ Nike He is stuck between a hard spot as usual industry guy wants to compare two non comparable items!
I feel for the poor guy!
-
13-11-2008, 08:55 PM #18
Re: Air conditioning energy consumption
-
20-11-2008, 11:48 AM #19
Re: Air conditioning energy consumption
This particular ventilation unit has the ability to temper the air. So during the winter it warms the ventilation air and during the summer it cools it.
I agree it can't be compared with a conventional air conditioning unit that's primary function is to cool the ambient room air!
-
20-11-2008, 11:49 AM #20
-
20-11-2008, 02:12 PM #21
Re: Air conditioning energy consumption
-
25-11-2008, 11:15 AM #22
-
25-11-2008, 11:18 AM #23
Re: Air conditioning energy consumption
I've always wondered about that (well, since I got into the whole thermal comfort/indoor air field). When you cool air it becomes more humid. But the actual water content of the air remains the same. So why does it feel 'wetter' since there isn't actually any more water in the air?
-
25-11-2008, 02:45 PM #24
- Join Date
- Sep 2007
- Location
- Split Croatia
- Age
- 57
- Posts
- 6,151
- Blog Entries
- 6
- Rep Power
- 36
Re: Air conditioning energy consumption
-
25-11-2008, 03:13 PM #25
Re: Air conditioning energy consumption
-
25-11-2008, 03:19 PM #26
Re: Air conditioning energy consumption
A major part of your body's cooling mechanism is the evaporation of moisture from your skin.
Less humid air is more absorbent and helps this process. In very dry climates the moisture evaporates so fast you may not even realize you are sweating.
More humid air is less absorbent and hinders this process, making you feel wetter because you are wetter.
Similar Threads
-
Ambient temperature and fridge energy consumption
By elita in forum FundamentalsReplies: 1Last Post: 08-12-2007, 12:32 PM -
Very High Energy Consumption
By gdiaz in forum Trouble ShootingReplies: 12Last Post: 17-01-2007, 03:56 PM -
need energy consumption data
By gokhan in forum Technical DiscussionsReplies: 2Last Post: 25-05-2006, 12:48 AM -
Direct Energy Consumption Question
By v8dve in forum FundamentalsReplies: 1Last Post: 05-04-2003, 03:31 AM