PMV Control

Help and discussion on using the Detailed HVAC option

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ricardo.filho
Posts: 3

PMV Control

Postby ricardo.filho » Sat Mar 17, 2018 10:53 pm

Hello, dear DB users,

I have a task to optimise operational costs while achieving a PMV value between -.5 and .5.
I am using a detailed HVAC, with a generic air loop, with a heating coil and a humidifier, and a ptac unit in each zone.

right, if I run the model using the air temperature control my operational cost is 55K per year, but my PMV levels are not always good, usually -.7 on average
(the building is in Amsterdam)

if I use the PMV control to run the simulation, my operational cost goes up to 57K only, but my PMV is always perfect, therefore I get a productivity increase of 24K.

is it considered "not fair" using the PMV control?
what would be the implications of using PMV control to run the model in real life? like would I need to "buy" special equipment? to allow my real HVAC to control the temperatures by the PMV levels?

thanks
msweeney0312
Posts: 5

Re: PMV Control

Postby msweeney0312 » Mon Mar 19, 2018 1:51 pm

PMV is a metric of occupant satisfaction within a space; there's no functional way to control an HVAC system to it (unless you can hook up electrodes to each occupant's brain and integrate that data within BACnet or something :) ) . However, PMV maps in a fairly straightforward way onto a Psych chart.

See this example:

https://en.wikipedia.org/wiki/Thermal_c ... method.png

Therefore, if you control to relative humidity and drybulb (and you stay within the PMV-related air velocity criteria and MET rates, etc.) you can loosely correlated to PMV. You may want to consider adding a cooling coil to the air loop (I'm assuming it's for ventilation) and then adding humidity controls to it to more tightly control humidity in the spaces, since PTACs generally only respond to drybulb temperature and will therefore only indirectly impact RH.

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