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Re: [EnergyPlus_Support] DX Cooling coil single speed
Dear Sandip,
DX equipment models mostly use a set of 4 curves that are generated using regression analysis from a matrix of performance data provided by the manufacturer. This matrix describes how the equipment performs under a wide variety of different operating conditions. The curves are each in their own right normalized around a set of "rating point" values.
There are two tools available that I have seen to help you setup (and possibly understand better) the performance curves in conjunction with appropriate rating point values (they go hand in hand). One is a spreadsheet tool that comes with e+ and can usually be found in your launch bar. The other is from DesignBuilder. I use my own, but only I understand how it works.
Be forewarned that this topic is probably the most advanced that the non-source-code writing simulation community can come up against. If you are a beginner e+ user, my advice would be NOT to start with the most complex issues first. If you have gained a basic understanding about part-load (part of "rated full load") performance together with the other factors influencing HVAC performance (like the humidity in the air and the temperatures of both air and cooling medium, as well as bypass factor) that should be enough for now.
The equation you wrote is one of several that are solved simultaneously using algorithms that converge on a solution. I'm sorry there is no easy answer. The interdependencies are simply too complex to solve by hand.
Perhaps you state what you wish your model should demonstrate. Then state what you have done and what you observed, followed by what you cannot interperate or generate for results.
Kindly yours,
On 5 Jul 2016 2:15 pm, "sandip gupta
sandipgupta_nh@xxxxxxxxxxx [EnergyPlus_Support]" <
EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
Â
Dear sir,'
While calculating the power consumption of a DX Cooling Coil Single Speed.
Step 1: Total Cooling Capacity as a function of temperature is calculated. Here from where does the Wet Bulb temperature comes from is it the sensor value.
Step 2: Total Cooling Capacity as a function of flow fraction is calculated.
Step 3: Qtotal = Qtotal,rated * (TotCapTempModFac) * (TotCapFFModFac) is calculated but from where do we get Qtotal,rated. Pls help.
EnergyPlus? Version 8.5 Documentation Engineering Reference Page Nuumber 785 calculations.
Please help me out how to calculate the power consumption of HVAC system for different set point temperature. Does the above calculations satisfy my requirements.
I would be very very thankful to you if you kindly solve my doubts and problems.
With Warm Regards,
Sandip Gupta.
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Posted by: Jean Marais <jeannieboef@xxxxxxxxx>
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