ENERGY MANAGEMENT PROJECT
PREPARED BY GURPREET SINGH BANWAIT
SUBMITTED TO IAN CARTER
The project is about the energy mitigation of the elementary school roch carrier which is situated in kanata 401 stonehaven drive .
we have been provided the utility bills of school of last 10 years. we have use these utility bills to extracy the data and put in the retscreen.
The analysis of the utility bills explained that the hvac system of the school is not working well after 27 /9 /2015 and , seems like some equipment is decaying, or worsening in terms of performance, day by day ,cycle by cycle
This graph illustrating the increase of the cusum and change of the slope after the vertical line , cusum is going positive means actual consumption is not equal to the baseline and thats why it is not close to zero , instead it is moving upward which is an indication of higher actual fuel consumption compare to the baseline predicted( based on the initial years with respect to hdd )
Here in this time series graph (regression ) we can see that there is a relationship between heating degree dyas and fuel consumption , higher heating days corresponds to higher consumption and also consumption deviates corresponds to the heating degree days.
Like in our case the overall loss that has been suffered by the school after 27 9 2015 is 72168 meter cube of gas . This figure has been computed by the software by considering the baseline predicted and its actual consumption that has happened after the 27/9/2015
So by rectifying the fault or problem due to which this over consumption is going on we can bring the consumption back to normall and can avoid this overconsumption of 72168 metr cube of gas
But the question is how to find the fault , or where the fault is , like in boiler , heat pump, fan coil unit ..... for sure some thing is decaying as said above losing its performance and resulting in higher consumption , but again it would all be our speculation. So we are suffering a loss of 24056 metre cube of gas each year which was not supposed to be happening with the model prediction
The blueprints has been provided by the ocdsb and after carefully studying those we observed that the water loop heat pump systm is installed in this school which is working in conjunction with the boilers.
We also observed that the lighting system is all of the fluoroscent types and the high bay are used of the metal hallide technology which is almost been working since 2004.
The overall time for which all equipment (ike electrical lighting, hvac which includes boilers , heat pumps , water loop electric pumps etc) are functioning for more than 18 years and showing a decay in their performance which acting as the higher utility cost of the school
A site visit was conducted by the four group members at the school for physical analysis of the heating hvac equipment
we measure the cop of the various heat pumps installed in the system and also their electric consumption , by reading their nameplate.
we also measure the illumination level at the site like in the classrooms , corridors, gym library etc , we also access the condition of the lampand fixtures, by considering they are 18 year old
we measure the pump actual wattage to find any over sonsumimg pump or motor is there.
we also inspected the building envelope , effective overall insulation of the wall and envelope
we checked boilers , their gas consumption rate and their current efficicency by considering they are 18 year old boilers and almost had been working with less efficciency than their nameplate as concluded in the regression analysis above.
The site survey revealed a comprehensive scenario of all the things that were being going on in the school.
The cop of the existing heat pump was found to be only 2.0 or even less than that , which was notified at the site survey.
The heat pumps which were performing worst were notified in the survey.
The boilers were also working at 70 percent efficiency due to the wear and tear they suffered by the continous operation during their life span of 18 years.which was totally unacceptable.
The illumination level of the site was not appropriate. we have found that the lux levels was not even reaching the desired minimum recommended level. The lumens output of the lamps were reduced thats why the illumination level was totally compromised at the site.
Some of the big water pumps like heating water loop pumps which were of the 7.0 kw are alo showing inefficiency in their operation.
The infiltration was also detected at the site due to the huge air leakage that was going on at the site due to the leaky windows and improper ventilation system in the building.
we have also detected a improper scheuling of the building operation almost 12 hours a day which is significantly high and unnecessary.
we are recommending sensors like occupant sensors , timers to make in operate in strict time band of 10 hours operation
we use all these valuable information in the retscreen to modell the project and tried various option to eliminate the problems of excessive enrgy consumption by the hvac system.
Some of the recommendation that we found that we should go with is like higher efficiency boilers , replacement of som eof the heat pumps , changing the compressors of some of the heat pumps.
Replacing low efficicency fluoroscent lighting with new high efficacy led lighting like t8 with led t8 and metal hallide high bays with led high bays .
Replacing high consuming big giant pumps with new high efficiency nema certified pumps , Addition of the vfd due to the changing load characteristics of the pupms
There are total 4 boilers whch were utilsed as a primary source of heating in the hvac system of the school. As we can see we are proposing a weil mclaim gv 90 plus boiler which is a condensing boiler and has a 95 percent efficiency. The initial cost of the four boilers are 14000 dollars and annual saving that can be achieved by installing these are 2570 cad. The simple pay back is 5.4 year which is not bad by considering the savings it can potentially provide to the ocdsb
In the heat pumps we have follow two approaches. first is to replace the faulty inefficient with new ones that we are suggesting of the daikin effinity horizontal models suited for ducted application and second approach we are following is to replace the compressors of those whose conditions had not been deteriorated as above faulty ones.
As we can see that by changing the compressor of the existing pump with new one the cop can dramatically be increased and the incremental cost is also very less compare to full replacement of the heat pump
The savings are almost equivalent to like a new heat pump can achieve compare to old inefficient one.
By investing 1000 dollar on new replacement and installion charge we can bring annual saving of 1500 dolar with this retrofit and we can see that the simple pay back period is also 0.7 year which is strong case that we should approach
In second approach we are replacing the whole heat pums which are big one and are working with very poor efficiency of almost 2.0 cop.
We are recommending the daikin effinity models for the replacement. and thses are highly efficient pumps with cop can reach almost 5.0 in best conditions.
The incremental cost of this heat pump which are total of 8 combining all the models are 26000 dollar and the annual saving of combining all these are 1000 dollars .
The pay back period of all these are also calculated in the retscreen model as described below. The models that we are recommending to replace are skh 042 , 048, 060. The pay back period is 2.7 to 3.0 years
In building envelope we have recommending a retrofit of the windows as they are leaky and significantly constributing to the air leakage and air infiltration.
The retrofitting work of all the windows are contributing to the incremental cost of just 5000 dollars but the energy we are saving due to efficient boilers and improved building envelope is amost 43470 kwh.
The ventilation of the sytem has been improved and by improving the ventilation controll , incorporating heat recovery ventilator , we can save the total energy of 178524 kwh of natural gas with annual saving of 1540 dollar and providing a simple pay back of 4.9 years with investment of 18357 dollar.
In terms of lighting we are recommending a led retrofit replacement of existing fluoroscent t8 lamps.
All the classrooms are filled with these lamps and a huge potential is there if we replace these with high efficacy led lamp there are total 840 lamps are there.
Hence 62546 kwh of energy can be saved by incorporating led t8 lamp.
The simple pay back is 2.0 years and the annual saving is 6255 dollar with initial investment of 12600 dollar
In the same way high metal hallide can provide a huge potential if we replace these with led high bay of high efficacy og 145 lmns / watt
Tol energy saved is 5738 kwh annualy and pay back period is also less than 5 years. with annual savings of 10000 cad in HIGH BAY GYM LIGHTING
In pumps we can save almost 73 percent of energy with nema certified high efficicency 92 % efficicency.
we also recommending vfd due to variable loads and getting a annual saving of 30 651 kwh of electricity/ motor
The pay back period is 1.6 years with annual saving of 3035 dollars per motor
FINAL CONCLUSION AND RISKS
15)Finally the possibility of achieving the saving of energy and cost are immense. Their is s solid business case that can be formed based on the energy and financial analysis. The immediate work should be done on the boilers side as we are loosing amost 24056 meter cube of gas annaualy due to the aging of the boilers which are primary heating equipment in our case.
Secondly energy and cost saving potential are also huge as described above in analysis. Heat pumps also need upgrade and replacement as they are primary field equipment and also work solely in summer for coolinng. Older heat pumps are also aged and end of their life expectancy like boilers. They are delivering poor cop as founded on the site vist.
In terms of risk there is a potential of escalating fuel prices in future like naural gas carbon tax hikes etc which can force our natural gas sytem be converted in to all electric hvac system which is risky as per todays business casse.