Green Team Heat Doctors

Background

Launched in 2007 by three dedicated employees, the BCIT Green Team (GT) now includes over 70 members representing schools and departments across the institute.  The GT’s mission is to reduce the institute’s ecological footprint by engaging BCIT employees through sustainability initiatives that create awareness, participation, and behavioural change.  Launching one green campaign every year is amongst the tactics used by the GT to realize its mission.

Buildings are typically heated in one of two ways: either through convective or through radiant heating.  Convective heating relies on blowing heated air into a space.  Examples of these types of systems include forced air residential furnaces, packaged rooftop units, and air handling/make-up units.  Radiant heating systems heat an object which in turn heats other objects and people in the space (as opposed to directly heating the air in the space) through radiant heat transfer.  This is the same form of heat transfer that allows the sun to heat the earth – it’s through radiant heat that your face can feel warm on a sunny winter day even thought the air is cold.  Examples of radiant heat systems in buildings include radiant floor heating, gas-fired tube heaters, and wall-mounted hydronic (hot water based) radiators (although wall mounted radiators, because of their design, ned-up transfer heat mostly through convection, with some radiation too).  One advantage of using radiant systems rather than convective systems to heat buildings is that the space can be controlled at a lower temperature setpoint with radiant systems without impacting occupant comfort.  That is to say, because radiant heat systems heat objects (including people), occupants feel as comfortable at a lower space (air) temperature than they would with convective heating systems.  Controlling heating systems at a lower setpoint can save significant amounts of heating energy.

Trades buildings (NE02, NE04, NE06 and NE08) located in the Factor Four Area are heated with natural gas-fired radiant heating tubes suspended from the ceiling.  All heaters are connected to thermostats whose temperature setpoints are controlled by a central HVAC (heating, ventilation, and air conditioning) control system (also often referred to as direct digital controls or DDC).  The Trades buildings also have large bay doors to allow delivery of large pieces of material and equipment. Each bay door is equipped with a sensor that signals the HVAC control system when the door is open.  This provides the functionality to be able to save natural gas for heating by lowering the space heating setpoints while the doors are open.

Problem and/or Opportunity

While conducting a high-level energy audit of building NE04 in 2010, a SEMAC student noticed that carpentry students were working in tee shirts while the shops’ bay doors were wide open in the middle of winter.  Upon further investigation, the SEMAC student learned that, due to their high levels of physical activity, the carpentry students were too warm and had to open the bay doors to remain comfortable while they worked.  The space temperature was measured by the SEMAC student at anywhere between 19 to 21 degree Celsius.  Through further investigation, the SEMAC student identified the following problems and corresponding energy conservation opportunities:

1. Given occupants’ level of activity, the buildings were overheated during occupied hours.  Reducing the occupied temperature setpoint would save heating energy.
2. Only the heaters closest to the bay doors were being controlled by the door switches while the remaining heaters continued to operate.  Because of the way they are controlled (i.e.: by one single thermostat measuring the room temperature), the other radiant heaters had to burn more natural gas in order to maintain that one sensor (i.e.: thermostat) reading at the setpoint temperature.  Integrating all radiant heaters with the door switches would maximise energy savings while the doors were open and allow meeting the original design intent of saving energy.
3. Heating setpoints had not been optimised for unoccupied hours.  Reprogramming the HVAC control system to lower the overnight temperature setpoint as low as possible (without compromising Trades materials and processes) would save additional heating energy.

Solution

The “Heat Doctor” project was initiated to devise a process to develop the energy savings opportunities, to implement the recommended changes in the Carpentry shop as well as all other trade shop of similar layout and design, and to monitor the results the changes had on energy consumption.  The process is summarised as follows:

1. Work with the students, Trades faculty, and Facilities staff to fine-tune (lower) heating setpoints during occupied hours to optimise comfort based on the specific needs of each area and to conserve energy;
2. Work with Trades faculty and Facilities to fine-tune (lower) heating setpoints during unoccupied hours without compromising the Trades materials or processes.
3. Work with BCIT Facilities at making the changes in the DDC system.
4. Monitor savings using the PUMA monitoring system (login: BCITStudent password: Student7).

This process was first pilot tested in 2010/2011 in the Carpentry Shop (NE4).  The occupied heating setpoint was reduced from approximately 20 degrees Celsius to 16 degrees Celsius while the bay doors are closed.  When the doors are open, the HVAC control system lowers the space heating setpoint to 12 degrees Celsius.  The unoccupied (overnight) setpoint was reduced from 16 degrees Celsius to 12 degrees Celsius.  Adjusting for weather variability, the pilot test confirmed that the changes saved approximately 270 GJ per year of natural gas (approximately 35% of NE04’s annual consumption).

Following the successful Carpentry pilot test, the Heat Doctor project was approved for rollout in the remaining Trades buildings (NE2, Joinery; NE6, Piping; and NE8, Welding).  The Heat Doctor, a component of the Green Team Heat Savers campaign, was the lead person in charge of applying the 4-step process described above and tested in the Carpentry Shop (NE4).

Through dialogue with Joinery faculty, the Heat Doctor identified requirements unique to the NE02 shop that had to be maintained through any changes.  These included ensuring that the joinery glues were not subjected to temperatures below their critical minimum storage temperature, that overnight temperatures remained warm enough to ensure proper glue setting/curing, and that thermal fluctuations were not great enough to negatively impact the wood itself. Note: the Factor Four energy management framework includes a category of action items called: Changes to Business Practices.  The Factor Four team noted that because of glues, a 2,000 m² shop has to be kept warm at night, when unoccupied. Maybe other glues exist that can cure at lower temperatures?  Or maybe those pieces of work that need the “warm glue” can be moved in a special (smaller) room at night so that the heated space is smaller?

A summary of changes made in each building and the associated expected annual energy savings can be found here.  Changes that were made in NE08 will be revisited and adjusted as necessary following the commissioning of the new welding ventilation system in 2014-2015.

Technologies Implemented

• Building HVAC control system reprogramming (i.e.: DDC reprogramming)

Energy Savings and GHG Emissions Reductions

Because the areas are not maintained as warm as they were in the past, the project will save natural gas costs and GHG emissions associated with burning that natural gas.  The table below summarises the natural gas savings expected in each building.

Building	Expected Annual Natural Gas Savings
	GJ [ekWh]	%
NE02 (Joinery)	n/a*	n/a*
NE04 (Carpentry)	270 [75,000]	35%
NE06 (Piping)	n/a*	n/a*
NE08 (Welding)	n/a*	n/a*

 * The implementation failed in all post pilot projects.  It seems like the changes made might have led to increases in energy consumption.  The team is unsure of what happened and had many difficulties working with the department in charge of making changes in the BCIT DDC system. There was finally one meeting between the person in charge and the Factor Four team and the conclusion was that only one IR heater had been tied to the changes and that the pother heaters were now compensating.  It also seem that there was an “if” error in the code line inserted in the DDC system.  The person in charge as since left BCIT it the Factor Four team has not had a meeting with the department since.  This meeting is on the team’s to do list.

Additional Benefits and Features

In addition to energy savings and GHG emissions reductions, the project significantly improved comfort for the students and faculty.

PROJECT FAST FACTS

• 270 GJ (75,000 kWh) of savings at almost no cost
• 35% of natural gas savings during pilot project
• Failure during implementation in other shops
• Has the potential so save 500 GJ (140,000 kWh) or even more

PROJECT PARTNERS

BCIT received the support from Fortis BC ($5,000) and BC Hydro Power Smart ($5,000) for the Heat Savers / Heat Doctor campaign. Thanks to both organisations for their support!

PROJECT FOLDERS

• DDC zoning (coming soon)
• Campaign planning documents (coming soon)
• Video from pilot project
• Video from full deployment of heat doctor
• Heat Savers campaign website
• Heat Doctor wrap-up memo
• CUSUM – Meter NE2 to NE6 Natural Gas (show both success and failure)