HVAC system energy benchmarks (for comparison)

[wroot]

Hi,

Does anyone know of a site or source where I can get energy consumption benchmarks for different types of system conditioning a space or serving a building?

The United Kingdom's CIBSE Guide F for instance has kWh/m2/year for VAV, CAV, fan coils, chilled beams + radiators etc, but I'd like even more if possible.

What I'm looking to be able to do is compare the energy consumption of the different systems when conditioning a space or building to the same conditions.

Source can be from anywhere in the world! I've found some older stuff in ECG019 and also a handbook produced by a company that shall remain nameless, and whilst they do have some benchmarking, it is highly out of date unfortunately. Had a look through ASHRAE handbooks but to no avail.

Any assistance appreciated!


James

 

[jkauwale]

Hi James,

Are you trying to compare two different types of A/C systems to see which uses less energy? Or are you just looking for average energy use for different A/C systems?

If you want to compare two different types of A/C systems,
I would suggest using a HVAC Load/Energy Simulation program like Trane Trace 700.

http://www.trane.com/Commercial/Dna/View.aspx?i=1136

I've used it for my LEED projects to compare the baseline ASHRAE 90.1 HVAC system to my design HVAC system. It will give you the amount of energy used for the year for both alternatives.

If you are looking for average energy use for different A/C systems, I would suggest the following two papers:
Energy Consumption Characteristics of Commercial Building HVAC Systems Volume I: Chillers, Refrigerant Compressors, and Heating Systems

http://apps1.eere.energy.gov/buildi...cial_initiative/hvac_volume1_final_report.pdf

Energy Consumption Characteristics of Commercial Building HVAC Systems Volume II: Thermal Distribution, Auxiliary Equipment, and Ventilation

http://apps1.eere.energy.gov/buildi...cial_initiative/hvac_volume2_final_report.pdf

Justin K, P.E.

http://www.engproguides.com

 

[wroot]

OK yeah - those volumes I and II have a few good references; I've been trying to get my hands on one of these CBECS reports, but the eia.doe.gov site seems to have shut down, which is causing me no end of trouble.

 

[SamFdc]

Are you attempting to find the difference between the A/C systems James?

http://www.aerotherm.co.uk/

--------------------------------------
<a href="

http://www.aerotherm.co.uk/industrial-home">industrial

ovens</a>
<a href="

http://www.aerotherm.co.uk/industrial-home">drying

ovens</a>
<a href="

http://www.aerotherm.co.uk/industrial-home">curing

ovens</a>

 

[wroot]

SAmFdc - yes I was wanting to compare the energy consumption between the different systems.

The demand for heating or cooling from a space will be the same annually for every system. What will differ is the auxiliary loads and distribution losses for each different type of system.

For instance, say we have an annual heat demand of 1.0MWh. Each system will burn more than 1.0MWh of gas to supply that space with heat (due to boiler efficiency and distribution losses), and will also consume a bit of electricity due to the pumping of the water to perhaps fan coils. And then there's electricity for the fans.

So I hope you can understand where I'm coming from. I would imagine the more centralised the better, i.e. VAV will consume the lowest energy in conditioning that space to the required level all year-round.

This website seems fairly good:

http://buildingsdatabook.eren.doe.gov/

and section 5.5.4 deals with auxiliary loads pertaining to a few different types of system (CAV, VAV, packaged CAV).


James