ERV & Economiser

[jeffcolledge]

I recently installed 4 rooftop units at an account of mine. All came with economisers. One unit is tied to an energy recovery ventilator. Most systems I've seen in the past use the external duct method of joining the two, leaving no room to install an economiser, however, in this situation, the duct joins below in the ceiling space. So my question is, do I still need the economiser? I believe I can still utilize the "free cooling" aspect of it, so why not? I just have never seen the two together before, so it got me thinking....what do you think?

[Dad]

Jeff,


A little more info please


Make, model

What type of business is it going in.

[jeffcolledge]

It's an ERV2000 cfm. It's joined to a 10-ton Carrier brand new unit, can't remember the m#. It's used in a restaurant in a closed off smoking section for ventilation.

[Dad]

Jeff

In my area the code states your RTU must have outside air intake of some kind so we must install the factory damper or econo. If your recovery ventilator satisfies that code then there would be no need to hook up the economizer for that one unit.

I would think you would need to change the air in a smoking room with outside air and some kind of exhaust or air removal and filtration.

Would it hurt anything to install the economizers?

Does the restaurant need the outside air to balance the kitchen exhaust?

[cynic]

Usually would say go for it and set the minimum position to 0% but if its a sealed off smoking area does the rtu have a power exaust or relief damper ? In other words when the economizer opens will it put that area into a positive pressure and push smoke and odor into the rest of the place ?

[Edited by cynic on 07-17-2004 at 09:29 AM]

[Dad]

Can you guys imagine what the filters and coil will look like in a few months?


Cynic... like R12 says... bring your can of oven cleaner!

Sell them a quarterly cleaning contract and get ready to pull that blower housing. Bring a supply of motor sheaves, the nicotine will make that belt stick and you know how the carrier units are with sheaves.

[jeffcolledge]

Cynic:
The exhaust blower on the ERV is designed to remove about 20% more air than the supply blower can deliver. So, yes, there is a slight negative in the space. My concern is when the econ. opens for free cooling, it may pressurize the space. I guess I can have an air balancer come in and set it up both ways, one with mechanical cooling and the other with free cooling.
Any other input or experience would be greatly appreciated.
Thanks guys.

Yes there is a barometris relief on the econ.