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ABSTRACT Utility bill tracking is at the heart of an effective energy management program. Merely comparing utility bills can yield inaccurate indications of the amount of savings from energy management programs due to the unaccounted influence of weather or other factors. Correcting utility bills for weather data will give more accurate representations of savings that were accrued. This paper presents the how and why of weather correction for those who want to become more familiar with the concepts and methodology. WHAT UTILITY BILL TRACKING CAN DO FOR YOU Jim Faes from Jefferson County School District wrote to me energy accounting is the backbone of our school district s energy management program. Why would he write that? An energy accounting system is much like an airplane s control panel. In order to correctly navigate your airplane nike air max 90 hyperfuse solar red , you need to understand where it is, where it was and where it is going. If you fly the plane without the control panel, you have a good chance of crashing the plane. It is the same with energy management. You need to know where you are, where you were, where you are going, and how where you are now fits with expectations of your progress. With utility bill tracking systems, Energy managers can: Enter target usage and costs and track their actual performance against their targets Discover large increases in energy usage and take corrective actions Identify the buildings that are using more $SQFT than the others, and concentrate energy management activities on those buildings. Determine whether your meters are on the best rates Check to see if you are being billed correctly by the utility Create bills for your tenants (if you have any) Determine whether you have saved any energy from your energy conservation measures Aggregate your usage and costs and pass this aggregated data to potential energy suppliers Create utility budgets More generally, if you keep aware of the state of your utility accounting nike air max 90 hyperfuse nz , you will know where your facility is and how it is faring towards your goals. UTILITY BILL TRACKING: THE REPORT CARD FOR FACILITIES AND FACILITY MANAGERS Energy Managers and some Facility Managers all to often have to justify their existence to management. How much did we save last year? Is that more than what we pay our energy manager? Did your recommendations give reasonable paybacks? Why do we even have an energy manager? There are several methods to determine whether you have saved energy from your energy conservation efforts, as described in the literature. You can wave your hands in the air, and decide upon a number; calculate your savings based upon data logger and control points; compare utility bills to determine savings; and finally, employ a building model. (These are referred to as Option A, B, C and D in the IPMVP, FEMP Guidelines and other literature.) Most likely, the simplest and most palatable method for the facility manager to determine whether you are saving energy is Option C, comparing utility bills. Why? Well nike air max 90 womens nz , although some utility managers do present calculations given to them by the friendly sales rep, this method is hardly reliable, as they may produce inflated numbers. Placing dataloggers and using existing control points seems easy enough, but converting these inputs into savings numbers can sometimes prove to be outside of the scope of the facility manager s skillset. Building modeling, while it can be useful, requires hours of time to construct the model, and may represent how much the building should be using, and may not really represent what the building truly is using. If those objections hold, that leaves utility bills as the last remaining method to quantify your performance as an energy manager. Plus air max 90 womens sale , in the end, it is all about the utility bills, as the bills reflect how much you are paying. Since most facility managers are already tracking their utility bills, it is only one additional small step to see whether you have saved any energy and costs from your energy management program. Just compare prior year bills to current year s bills, and you will see if you have saved. Well, it isn t that easy. Let s find out why. HOW WEATHER CORRECTION WORKS Rather than compare last year s usage to this year s usage, when we use weather correction, we compare how much energy we would have used this year to how much energy we did use this year. Many in our industry do not call the result of this comparison, Savings nike air max 90 for sale , but rather Usage Avoidance or Cost Avoidance. But, since we are trying to keep this paper at an introductory level, we will use the word Savings. When we tried to compare last year s usage to this year s usage, we saw Figure 3, and a disastrous project. We used the equation: Savings = last year s usage this year s usage When we use weather correction, we end up with Figure 5, and use the equation: Savings = How much energy we would have used this year how much energy we did use this year** **where this year s usage from the 1st equation is the same as how much energy we did use this year from the 2nd equation The next question is, how do we figure out how much energy we would have used this year. This is done using weather correction as shown below. First, we select a year of utility bills we want to compare future usage to. This would typically be the year before you started your energy efficiency program nike air max 2015 nz , or the year before you, the new facility manager, were hired, or some chosen year. In this example, we would select the year of utility data before the installation of the chilled water system. We will call this year the Base Year. As shown in Figure 6, we graph Base Year usage versus weather (in the form of Cooling Degree Days or Heating Degree Days). The blue dots represent the utility bills. Then we find the Best Fit Line between usage and weather. The Best Fit Line is the line that comes closest to all the utility bil锘.
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| Beitrag vom 21.11.2015 - 12:50 |
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| vivianlee |
21.11.2015 - 12:50 |
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| kiyoumins |
24.11.2015 - 09:43 |
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