I am using an 'air load' calculator which gives me a total cooling load in kBtu for an installation based on the cfm for different locations around the US.
The figure that I get is the cooling required to bring the air temp down to the required set point but I want to be able to convert this figure to the required electrical load for the whole cooling plant.
What I am looking for are some 'rules of thumb' for coming up with the calculation.
The air supply that is being cooled will be provided via an AHU ( air handling unit ) and the systems are 'full fresh air' ( no re-circulated air ) and I assume that it will have a dx coil or a cooling coil operating on chilled water.
I have looked at packaged chillers on the web and have a good idea of the general power input to cooling load output --
what I need now is an idea of the efficiency of a cooling coil and the associated pipe work.
I have a methodology for different heating systems e.g. if we have a gas fired boiler providing low pressure hot water to a coil in an AHU I assume an efficiency of 80% for the boiler and an efficiency of 66% for the heat tranfer to the air ( includes pipe heat losses and heat tranfer in the coil to the air )
Can I assume a similar 66% for a chilled water circuit through a cooling coil ?
If we are using a dx coil in the air stream -- what is the efficiency of the cooling ?

As you have probably guessed, am an electrical engineer not a refridgeration engineer.

HELP