Wednesday, April 10, 2013 7:00 p.m.
Municipal Meeting Room
16 Station Avenue
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Welcome to The Brunswick School Dept. Facilities & Projects Site.
Much Like The Facilities Department, this site will be in constant motion.
Wednesday, April 10, 2013 7:00 p.m.
Municipal Meeting Room
16 Station Avenue
For the latest geothermal and HVAC energy usage reports click the following Hobolink. To review the combined BTUh transfer and electricity usage reports check this blog space often or read past blogs entries.
The link for Brunswick School Dept. Energy, sorry but Google documents has butchered my Excel file graphics. If anyone finds it to be of value, please email me and I will send the actual file. I would suggest that you scroll towards the bottom and look at the charts that show the 3 years of activity. # Note, HBS is a new school building.
As a facility manager, “in my opinion,” you need to know what it costs to operate any and all buildings on at least two levels. There are times when you will need to evaluate just how efficient your building’s systems are on a cost per square foot basis. Without a baseline and continuous tracking how will you ever know if your building improvements and energy saving measures are worthy of the costs? There is a good chance that you could keep repeating poor energy improvement decisions. If you have no ideas what your energy dollars are going to, how can you establish any priorities for future projects? Of course the “benchmarking” comparisons should be based on equal buildings or year after year comparisons. It isn’t a good benchmarking comparison to have a building that meets current ASHRAE, fully ventilated, measured against a building that only offers ventilation by open windows. That also brings us to evaluate a decision on a comfort basis VS the dollars saved basis. By bringing a building up to current standards of ventilation there is a good chance that your energy costs will increase.
The 2nd consideration for understanding a building’s efficiency is how much does this building cost us per square foot? In recent years there were many schools that have had to face shut down across the country. With student enrollments decreasing towns have had to look at bottom lines and the cost to operate a building as measured by the amount of students or employees. In my past life I had an administrative building that cost $522.00 per occupant per year and that was compared to $89.00 per occupant per year in an elementary school. With the new school building, capital construction program being reduced in recent years, should communities be looking at tucking non-education functions into school buildings so the systems costs can be shared and minimized?
Along with that thought, is efficiency the only consideration here? Just like everything else, these decisions are never that simple. At first glance it may seem simple but there are many factors that come into play. Safety, security for the staff and students for one, do we want the general public visiting the administration, sales people and such, that come and go? I do believe one thing, communities will have to rethink how they plan for replacing or updating their school buildings.
So in my last blog I asked the question how much does it cost to heat or cool a school building using Geothermal Energy? I have been gathering electrical energy usage data for all systems involved in the Harriet Beecher Stowe School HVAC system. If you click the link Data it will take you to a Google Docs spreadsheet that details days of readings in 6 minute intervals. This data is a combination of automation trending software and HOBO Data logging software.
Don’t click yet! Click too soon and you will be doing some serious scrolling. Along the far left there are small up and down arrows that will expand the data and show the entire day. Along the top row you will find a description of the underlying content. Columns N and O are for BTUh data and you will notice that some of this is represented by a negative value. Most of this happens during unoccupied building status and the BTUs actually exchange in reverse. Please note that anything reflected by a negative is formulated as a zero.
Column R is the KWh usage for that 6 minute snapshot.
Column S is the KWh value x $.13 and that is the average KWh cost for the month including demand and KVAR.
Columns T, U, V, W are the daily summaries.
1st line = Total KWh for the day
2nd line = Total C.M.P. cost for the day
3rd line = The amount of BTUs extracted from the geothermal field for that day
4th line = Cost to condition the building per square foot.
5th line = Average outside air temperature for that day
As you scroll down and observe the day to day totals, you can easily see the benefit of automation. By using the night time set back in a building you can save approximately 50% of your energy costs for 2 days a week. That savings also reflects the savings during the night set back during the week. The systems in this building start ramping up at 5:10AM and shut down at 4:00PM. On school snow storm cancellations or non-school session days we will set the systems to administration areas only because we will have limited occupancy. That reflects the value of training key building people to manage their systems with automation.
HVAC systems included in this data
H=Heating, water to air heat pumps, unit air handlers and ceiling mounted radiant panels
V=Ventilation, ERV, (energy recovery ventilation) operation of CO2 demand ventilation in all spaces
AC=Air Conditioning in all school and administrative function spaces.
Geothermal Energy is free, isn’t it? It is, as long as it stays in the earth.
How much does it cost to pull it out of the ground? Pumps need to circulate the water through the “closed loop,” system. Even on days when we hardly need any heat, we still need to keep pumping it. At times, in the shoulder seasons the water will just loop through a bypass connection and go back to the wells. The HVAC systems have a specific range of water flow so the flow rate is automated and adjusted as needed.
How much does it cost to extract the BTU energy from the water and convert it to air so it can heat or cool a space? How much does it cost to pump it throughout a building? Well, first off, you need to know how many BTUs have been removed from the water and the gallons per minute flow rate. That can be derived from the difference in temperatures of the water going out, subtracted from the water coming in. Knowing how many BTUS are being used at a given time, and the usage of KWH at that given time, allows me to determine that actual cost per BTU of geothermal energy being consumed.
Facilities staff need to track and understand their energy costs so that they know what is working efficiently and what isn’t during various times of the year. When you have a gas or oil boiler you simply add the usage on the monthly or delivery invoices. How can you track all of the electrical energy if you do not have it metered separately?
I have asked the smarter than I, people at Onset if they help me design something. Long story short, they gave a list of parts and pieces and over the past few weeks I have turned my office into a workshop (Left photo). The next picture is what all of the components look like put together and in place. I have just started gathering data and I will be posting my findings as they accumulate. Ideally I will be posting the data alongside of my C.M.P. bill so that we can compare the percentage of power between geothermal and everyday power needs. I would like to know what others have done to track the electrical load needed to power their geothermal systems.