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New Trends and Products in HVAC Control (Part Two)

Continuation from fall 2012 column

Steven R Calabrese

Steven R. Calabrese
Control Engineering Corp.

Contributing Editor

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Last year in the October installment of this column, I presented several current trends that are impacting our industry, and the products that go along with some of these trends. At the end of the column, I asked for your ideas for other new trends and products to write about. Well, I received quite a few emails, and so I thank you for your support, and present to you this month a few of those that I thought were worthy of discussion, as well as being uncomplicated enough for me to understand and describe. So here they are!

Wireless Switch Transmitters / Control Relays

Ever hear of the Enocean Alliance? From their website, they are a “consortium of companies working to further develop and promote self-powered wireless monitoring and control systems for sustainable buildings…” So they play a big part in the development of wireless devices as the one that is the topic of this discussion.

The wireless switch transmitter is, from its appearance, a wall mounted switch that looks like a light switch. Which is what it is. Except that it can do more than turn a light on and off, and it does what it does using no wires and no battery! The switch generates a small amount of electricity when pressed, enough to send a signal to a nearby control relay (nearby meaning within 100 feet or so, and that would be pushing the limits). The relay requires power, however you’re switching 120-volt power with it anyway in a typical lighting application, so you just need to bring the neutral to it as well as the hot.

The switch has several selectable modes of operation, including momentary mode and rocker mode. In momentary mode, the switch acts as a momentary pushbutton; the relay activates when pressed and deactivates when released. Could have some good applications. However the rocker mode is the most common. Throwing the switch one way activates the relay, and throwing the switch the other way deactivates the relay. Just like a normal light switch.

As stated above, the wireless switch transmitter / control relay has its applications in lighting, however a little “thinking outside the box” and you can find dozens of uses for this bad boy in HVAC controls. What comes to mind for me are all of those simple little situations in which you need to get “from here to there” but hardwiring would be prohibitive or extremely costly. Not to give any specific applications here, for I’ll leave that up to you!

Internet Thermostats

Way back in 2009 (a long time ago in terms of technology) I attended the AHR Expo, held in Chicago that year. I ended up doing a product review on something that was a relatively new concept at the time. The device is a residential grade thermostat that connects to the Internet using a WiFi chip that ties into your home’s wireless network. The stat has a touchscreen and is fully programmable, can access the weather, and has Demand Response capabilities built right into it.

Demand what??? Demand Response is a process by which a facility will automatically shed its electrical load in response to a signal from the Internet. Without getting too into it, suffice it to say that there are signals available via the Internet that have to do with peak events and electricity price changes. Well, this thermostat can act upon such signals, to avoid peaks and shed electrical usage when prices are high. Pretty neat stuff.

The thermostat is accessible via your smart phone, for remote programming and remote control of different parameters, remote monitoring of temperatures and other variables, remote notification of various alarm conditions, and remote troubleshooting. A long time coming, but apparently we’re finally there! To control your heating and cooling equipment, in a mobile manner, from anywhere in the world, is pretty remarkable. But I guess we kind of expect to be able to do that by now, huh?

Wireless Pneumatic Thermostats

I read about these recently, and had one of those “it’s about time” moments. The typical application is the pneumatically controlled VAV system that you would find in an older commercial office building. The terminal units (VAVs and FPBs) have pneumatic damper actuators, controlled by pneumatic thermostats in the spaces served. Short of committing to a complete DDC retrofit of the terminal units, what could be done to upgrade these units to a more current mode of operation and control? Well, here’s your answer! Installation is simple. Replace the existing pneumatic thermostat with a new, battery-powered wireless thermostat. The new thermostat controls the terminal unit much like the old one did, however the wireless feature allows BACnet communication with a central transceiver that connects to a Building Automation System (BAS). So you get BAS control of space temperature setpoints, including time-of-day scheduling and unoccupied mode override capabilities. And you get space temperature monitoring, which you can use in DDC strategies such as air handler discharge air temperature setpoint reset. Trending, alarming, troubleshooting…all the things that go with DDC control. So in short, the terminal units stay pneumatic, yet at the same time become “one with the BAS”!

Economizer Module

For rooftop unit OEM and retrofit applications, several manufacturers have for years offered “economizer control modules”. These modules are either factory-installed in a typical rooftop unit, or are put in “aftermarket” as a replacement or as an upgrade. They consist primarily of a “main brain” module that controls the economizer (outside and return air) dampers of the rooftop unit, to provide free cooling when outdoor air conditions permit. Also wired into the main brain are outside air temperature and humidity sensors, or more commonly an outside air enthalpy controller. The enthalpy controller senses both temperature and humidity, and typically has a setting on it that you adjust depending on the climate. The setting is/was somewhat rudimentary, meaning that there are no actual values on it that correspond to the OA temperature + humidity, only letters that indicate how “aggressive” you can be in setting the enthalpy “setpoint”, that point at which you would allow/disallow economizer operation.

Reliable Controls Now comes a new twist on the trusty ole economizer module. Yep, another “it’s about time” moment for me! A major manufacturer has just released a new product that allows you to input the ZIP code in which the economizer is to be installed. So no more guesswork and no more fiddling with the changeover control. Just pop in the code, and you’re good to go for the climate in which you’re in. More to it, of course, but still an idea whose time has come.

Energy Dashboards

The term “dashboard” has been around since we’ve been able to drive, however recently it has taken on a new meaning in our industry. So what is an energy dashboard? In simple terms, it’s an interactive energy measurement and management tool. Typically rooted in a facility’s Building Automation System (BAS), it utilizes data gathered from sensors and electrical meters, and presents information in an easy-to-understand format that caters to “the common folk”. Which isn’t to say that you can’t “drill down” to find more detailed information. But the primary focus of a dashboard, just like the one you have in your car, is to give you basic information from which you can act upon and make better decisions on how to operate your vehicle, or in the case of the energy dashboard, how to operate your facility. In a nutshell, the energy dashboard is a tool that can be used as a means of tracking energy consumption, in order to reach energy efficiency-based goals. In other words, to reduce energy usage and save money!

So where does it exist? Well, given that a particular energy dashboard is derived from a facility’s BAS, then it exists within the BAS, or more specifically, typically in a web server. So accessible via the Internet, just as the BAS is. The difference is that, the energy dashboard won’t allow for any modifications through its means of interface, which could be a personal computer hooked up to the Internet, or perhaps a smart phone with web access. Or you may be familiar with the kiosk style display or interactive touchscreen that we see more and more of in the lobbies of commercial facilities and multi-tenant office buildings. In whatever form it takes, the premise is the same: make this information available and visible to the average Joe, give them some means to interact with it, and encourage the notion of using it to benchmark energy usage and to promote efficiency within the facility. What a great concept! I’m actually thinking of setting one up in my own home!

Tip of the Month: Remember that first topic? Challenge yourself to come up with five applications in which you could utilize a wireless switch transmitter and control relay. Jot them down and save the list for future reference. Betchya it won’t take long to put one of those applications to practical use!


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