Johnson Controls T600: How to save energy in portable classrooms Part 1

If you have portable or modular classrooms you know how hard it is to implement energy saving temperature control strategies. Johnson Controls has the answer with the Johnson Controls T600 family of thermostat controllers.

To understand the elegance of the solution Johnson Controls provides with the T600 series of thermostat controllers, you must first understand the problem that portable classrooms provide from a control strategy perspective.

With school districts and universities across the country looking for ways to accommodate the increased demand for student classrooms, the portable or modular classroom proved to be a low cost solution. Over thirty six percent of the nation’s schools use these type of classrooms. Look around just about any school and you will see dozens of these classrooms adjacent to school buildings. These portable classrooms need heating, cooling, lights, and exhaust fans. To control them is not that difficult: a thermostat for the heating and air conditioning and a switch to turn the lights and fans on and off. Conserving energy in a portable classroom is another story. In Florida alone it is estimated that there are over 25,ooo portable classrooms each using more than 30 Kwh per day. That number gets even larger if the HVAC and lights are left to run in the occupied mode when the classroom is unoccupied.

One of the key energy savings strategies for portable classrooms is to reduce the electrical load by accurate temperature control and by making sure that temperature set points are set back during heating season and set up during cooling season when the class room is not occupied, and that the lights and fans are off when the class room is not being used. ASHRAE studies have shown energy savings as great as 36% to 47% implementing proper control and equipment strategies.

Time of day control strategies seem simple enough; either replace the thermostat in the portable classroom with a programmable thermostat or control your portable classrooms with your existing building automation system. The first option is not practical from a operation standpoint and the second option is usually too expensive. The challenge with programmable thermostats in portable classrooms is that the schedules in schools tend to change during the school year, and if you have a lot of portable classrooms you have to constantly send someone to reprogram the thermostats every time a change is made. Most school buildings have a building automation system that has the flexibility to either have all the holiday programs for the school year programmed in advance or the ability  to make a schedule change for an entire building with a simple key stoke. It would be ideal to use this system to control the portable classrooms, but because the classrooms are portable and not connected to the building the cost to run wire, including digging trenches, is usually too high.

Johnson Controls has a proven low cost solution. They have taken a very accurate programmable thermostat, added a passive infrared occupancy sensor and an extra relay. The result is simple but effective. You program your thermostat as you would any programmable thermostat, but during the occupied program times if the occupancy sensor does not sense movement after a programmed amount of time it puts the HVAC and whatever you have hooked up to the auxiliary relay in the unoccupied mode, guaranteeing your equipment only runs when the classroom is occupied.

Johnson Controls has several different models of the T600 series of thermostats that we stock at Stromquist & Company. The Johnson Controls Communicating Thermostats, the Johnson Controls TEC1100 thermostat, the Johnson Controls TEC210x-2 Thermostat you will note that have both Lon and BacNet versions, as well as the Johnson Controls Wireless thermostats.

As an extra incentive Stromquist Company is offering 10% off the following Johnson T600 thermostats through the end of October 2010:

Johnson Controls T600 HCN-4+PIR

Johnson Controls T600 HPN-4+PIR

Johnson Controls T600 MSN-4+PIR

 This special is only available when you order on line at our web store at

Be sure to check out Part 2. Mike gives a very in depth presentation on this great family of Johnson Controls thermostats.

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