Wireless controls for many single-zone systems

[oofowf]

I am working with a portfolio of healthcare facilities - all of the buildings are 1-2 story residential care facilities and served primarily by single-zone packaged or split DX air-cooled heat pumps. The combined tonnage and related energy cost for comfort control is outrageous when viewed in aggregate (California electric rates), even though each system is only 1-6 tons each.

The client's goal:
Take control of each zone out of the hands of the occupant and into the hands of one facilities manager
My hidden evil agenda:
Implement and maintain setbacks to save energy cost across the whole portfolio of 30 buildings

A colleague suggested looking into wireless communicating thermostats. I am not familiar with these.

My questions:
Any recommendations on wireless communicating thermostat products with a web interface?
Would an actual EMS be a better solution, e.g. an Alerton campus-style system? 1st cost and maintenance cost seems like a barrier there, as well as end-user is not that sophisticated.

The group's thoughts are appreciated.

 

[ozmosis]

Maybe look at zigbee based systems:

http://www.zigbee.org

 

[cdxx139]

EMS is the solution. I wouldnt worry about end user sophistication, they graphics are great now and very use friendly, especially Alerton. Plus you would specify at least 40 week training with the system. With wireless, I believe you will still need a front end, so the only additional cost will be fishing the wires. Easier to do for a 1-2 story building!

Do your homework on wireless. If an old building sometimes it has difficulty "reading" through concrete floors, which means more recievers and more cost.

Another drawback is battery life. Depending on the number sensors, figure battery life length and changing them (cost = both batteries and labor)

Unlikey solution, but how old are the units? You may implement a master plan as you change out the packaged units you upgrade to EMS? 1-6 tons of old technology is probably single stage cooling. Very choppy space temps, its all or nothing for the cooling. New technology gived you variable scroll compressors.

knowledge is power

 

[IRstuff]

One thing to really keep an eye on is whether whatever you are going to install will be sufficiently secure from hacking. If nothing else, you need to make sure that nothing extremely bad can happen if the wireless remotes are hacked. You'd need to use as many manual limits as possible so that the system cannot do any sort of runaway behavior.

The simplest type of system is X10, which mostly uses powerline communications, with RF repeaters. Setup is the simplest, but the controllers tend to be relatively more primitive. Device ID consists of a "house" code and 16 unique codes per house code. Little rotary selectors setup the codes and everything more or less works. This system is the most plug&play of any of the systems I've used. One nice thing that X10 has is a pure mechanical relay switch that works well with LED Christmas lights. Most of the other systems will still have some trickle current that's enough to simmer the LEDs, so that if it's really dark, LED lights will be observable as dimly lit.

Insteon is also a powerline system with RF repeaters. The controllers are slightly more sophisticated than X10's.

Z-Wave is a purely RF based. While I really like their controller capabilities, the setup is more complicated and involved.

What's complicated about the RF based systems is that the device IDs are much more complicated than X10's. Each device needs to be registered with each controller, and there does not seem to be a simpler method.

I've used all of the above, but haven't used any ZigBee system, but my usage tends to be limited to controlling lights.

TTFN
faq731-376

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[DRWeig]

Disclosure: I worked for Kele for 15 years and am now a consultant to them.

Browse here:

http://www.kele.com/network-and-wireless.aspx

Competitive products are also available from BAPI at

http://www.bapihvac.com

and a number of others.

They're all designed for building automation systems. I could name you 50 malls that have these things controlling their rooftop units. If you can afford it, that's the way to go.

I'd check those things out that IRstuff mentioned too -- I'm going to!

Best to you,

Goober Dave

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[NegativeZero]

I recently went to a Carrier presentation on wireless controls they are selling in my area called

http://www.founten.com/

there are some limitations but will work for what you need.

But everything you are looking to do a thermostat can do. Not sure why you would want to go to the expense to change it all out. There are many 7 day 24/7 stats you can lockout or give it a range of 2* and can program Occ times. The other option is to put a remote sensor and put the stats in a locked room or in the main office. This is done a lot.

EMS would be good if you have to money. Because, if the systems were not installed for controls it could get expensive. But its worth the research. But if you many that are not multizoned than I would stay with Stats....IMO

I would not jump to the conclusion that replacing or locking out stats is the answer, yes it will most certainty help. But it may be how the place is running. Looking at the PMs, equipment age, how the place is ventilate and what are the temps required or expected to be maintained and determine if the you have enough capacity. do this before you run out a pay for a complete new control system and your no better off.