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FARM ENERGY AUDIT REPORT
For
NYSEGJohn Zabliski
Manager, Agricultural Sales & Marketing79 Clark St
Canandaigua, NY 14424Phone: (585) 771-2660
Of the
Controlled Environment AgricultureLettuce Growing Facility
Bob LaDue 10 Pinckney RoadIthaca, NY 14850
Phone: (607) 347-6767
Prepared by
DLtech, Inc.Eric L. JohnsonPO Box 3910
Ithaca, NY 14852Phone: 607-266-6401
Fax: 607-266-7037
July 8, 2003
2
TABLE OF CONTENTS
EXECUTIVE SUMMARY..................................................................................5Summary of Energy Purchased & Related Data ..............................6Recommended ECM’S for Growth Chamber ..................................6Recommended ECM’s for Greenhouse ...........................................7Recommended ECM’s for Natural Gas Fired Boiler Operation .......8
ANALYSIS OF ELECTRICAL ENERGY USE..................................................9Electrical Energy Use by Equipment Category ...............................9Electrical Use by Area ....................................................................10
PURCHASED ENERGY ANALYSIS ................................................................13Electrical Energy Purchased............................................................13Natural Gas Purchased ...................................................................18Electrical Equipment Inventory ......................................................20Tabulation of Energy Purchased - Electrical & Natural Gas ............22
Appendix A -CEA Greenhouse Monitored Load/Use Data Natural Gas Equipment ........................................................................26
3
TABLE OF TABLES
Table 1. Electric & Natural Gas Costs for CEA Greenhouse…………………………….6
Table 2. Energy Use by Equipment Category………………………………………….. 10
Table 3. Summary Annual Electric Use……………………………………………….. .13
Table 4. Total Connected Loads………………………………………………………...14
Table 5. Summary Annual Gas Use………………………………………………..……18
Table 6. Equipment Inventory: Size and Power………………………………………...20
Table 7. Estimated Energy Use by Equipment Type, monthly………….………………21
Table 8. Electrical Energy Purchased - Jan. 1999 to Jan.2003………………………...22
Table 9. Natural Gas Purchased - Jan. 1999 to Jan. 2003………………………….…..24.
4
TABLE OF FIGURES
Figure 1. Energy Use by Equipment Category…………………………………………..9
Figure 2. Areas of Energy Use…………………………………………………………...10
Figure 3. Energy Use in Greenhouse ……………………………………………………11
Figure 4. Energy Use in Growth Room …………………………………………………11
Figure 5. HPS Growth Light Chiller Load……………………………………………….12
Figure 6. Walk-In Cooler Load…………………………………………………………..12
Figure 7. CEA Greenhouse Connected Load by Area…………………………………...14
Figure 8. 2002 Monthly Demand Profile………………………………………………...15
Figure 9. 2000 Monthly Demand Profile………………………………………………...15
Figure 10. 1999 Monthly Demand Profile……………………………………………….16
Figure 11. 2002 Monthly On/Off-Peak kWh…………………………………………….17
Figure 12. 2000 Monthly On/Off-Peak kWh…………………………………………….17
Figure 13. Monthly Natural Gas Use 2000-2002………………………………………..18
Figure 14. Monthly Therms per Degree Day 2000-2002………………………………..19
5EXECUTIVE SUMMARY
The Controlled Environment Agriculture (CEA) Greenhouse is a technology demonstration anddeployment facility based on “high value” lettuce growing. The facility is operated by CornellUniversity’s Department of and Biological and Environmental Engineering. Currently Romaine andBoston type lettuce are produced with the potential for 500,000 heads of annual production.
The CEA Greenhouse, located on Pinckney Road, Ithaca, New York, is a hydroponic growing facilitythat can produce up to 1,400 heads of lettuce each day. The CEA Greenhouse consists of an 8,000 sq.ft. glass greenhouse with four hydroponic growing ponds providing 6,400 sq. ft. of growing area. Anadjoining 3,840 sq. ft. head house provides space for the growth room, packing/processing area,walk-in cooler, work and computer management system and a utility room. Housed in the utilityroom are the natural gas boilers, electrical service and distribution equipment and computer controlsystems.
This complex energy intensive facility utilizes a wide array of technologies to produce a fresh,uniform, pesticide-free, HACCP-certified, high quality lettuce crop, independent of outside weatherconditions. This is accomplished using a computer controlled growing system that balances all aspectsof plant growth.
The process begins in the growth room where seeds are started and kept for 11 days continuallyexposed to the light energy emitted by twenty-six, 600 watts of water-cooled High Pressure Sodium(HPS) lamps. The plants are then transferred to hydroponic ponds in the greenhouse where theycomplete their growth cycle after approximately 24 days. All environmental conditions are monitoredand controlled to maximize production.
Electricity and natural gas are the energy sources utilized to produce the optimum environmentalconditions for plant growth. Natural gas is used to satisfy all thermal heating requirements. Electricenergy is responsible for operating an extensive range of equipment to complete growth. Thisincludes HPS supplemental lighting, ventilation, circulating pumps, evaporative cooling, humiditycontrol, shading, nutrient distribution, refrigeration, heat transfer and system supervisory control.
The application of energy conserving technologies in the CEA Greenhouse is uniquely defined by thegrowth requirements of the crop. The distinct energy needs for supplemental lighting and heating;ventilation and nutrient delivery offer a very narrow band of opportunity for energy managementoptions. Although sweeping reductions in energy use cannot be made, there are opportunities to finetune present use through appropriate energy management techniques, changes in control schemes andadoption of energy conserving technologies.
The following Energy Conservation Measures (ECM) are based on analysis of equipment energy useand operating costs within the facility. There may be other management, performance, operational,and maintenance factors that should be considered when evaluating a recommended ECM. Theefficacy for any recommended measure will vary depending upon conditions in the greenhouse andinteractions with other processes present.
6Summary of Energy Purchased and Related Data
Table 1. Electric & Natural Gas Costs for CEA Greenhouse2002 2001 2000 1999
Electric $ 42,175.34 $ 50,010.33 $ 68,085.68 $ 52,892.43 Nat. Gas $ 29,051.19 $ 30,051.86 $ 33,634.27 $ 15,636.64 Total $ 71,226.53 $ 80,062.19 $ 101,719.95 $ 68,529.07 Ave. $/kWh $ 0.0818 $ 0.1015 $ 0.1026 $ 0.1180 Ave, $/Therm $ 1.0053 $ 1.1519 $ 0.8726 $ 0.7539
Energy Costs per Unit of Production 2002 2001 2000 1999Combined Energy Cost per Head Produced $ 0.20 $ 0.22 $ 0.28 $ 0.19 *Electric Energy Cost per Head Produced $ 0.12 $ 0.14 $ 0.19 $ 0.14 *Natural Gas Energy Cost per Head Produced $ 0.08 $ 0.08 $ 0.09 $ 0.04 *Theoretical Annual Lettuce Production 500,000 Heads * not at full production
Combined energy costs have shown a gradual decline over the past three years. This decline is alsoevident in the unit cost of energy per head of lettuce produced. On the electric side, annual kWhusage has declined roughly 25% in 2002 and 2001 compared to 2000. The decrease in kWh use isprimarily due to updated control systems and better energy management practices. There has alsobeen a 20% decrease in average kWh cost ($/kWh) from 2000 to 2002.
The distribution of energy costs started out in 1999 to be 77% electricity and 23% natural gas. Thishas evolved in 2002 to 59% electric and 41% natural gas principally caused by reductions in electricuse and cost.
Natural gas energy use has declined 10% in 2002 and 2001 over 2000, due to turning off the boilersduring summer months and a decline in Degree Days during those heating periods. The lessenedheating requirements were able to offset the increases in cost per therm of natural gas.
Recommended ECM’s for Growth Chamber
Installation of a ventilation system for removal of waste heat from the area above the growth room. Athermostatically controlled ventilation system should be installed to reject this waste heat to theexterior during temperate seasons. Exhausting this heat in the summer will also reduce thermal gain tothe growth room that the air conditioning system must remove. When heating is required in the headhouse, this waste heat can be utilized as a supplement.
Waste heat generated by remotely located ballasts for the HPS lights cause excessive temperatures inthis area. These high ambient temperatures will contribute to premature ballast failure and can posean increased combustion hazard. A potential heat gain in this area of 7,900 Btu per hr. is estimatedfrom ballast loss.
7Investigate options for alternate methods of removing heat from the 15.3 kW of water-cooled HPSlights in the growth room. Currently waste heat from cooling water is rejected to the atmosphere by a4 hp chiller located outside the head house. Although the operation of the chiller is critical to theoperation of the HPS growth lights, the heat discarded is unused and offers a potential area of energyconservation.
The electric energy use for the chiller, circulating pump and condenser fans was monitored for 7 dayswith a Micro Data Logger (MDL) to accurately assess its precise energy use. Based on this data anestimated annual electric energy use of 38,281 kWh at a cost of $3,130 was calculated. Thisrepresents 21% of the electricity used in the growth chamber and 7.4% of the total electric use.
The 48,320 gallons of pond water present an attractive alternative heat sink for rejection of the wasteheat produced by the HPS grow lights. The growth light chiller removes approximately 30,000 Btu/hr. Daily heat production from the growth lights would raise pond water temperature by 1.8 ºF.
Transfer of heat from the HPS growth lights to the air in the greenhouse provides a second optionwhen supplemental heating is required, thereby replacing a portion of space heating supplied by thenatural gas fired boiler. The strategic placement of water to air heat exchanger(s) in the greenhousewould transfer the unwanted heat from the growth chamber to the greenhouse.
Annual savings of $2,500-$3,000 in chiller operating costs would support an investment of $7,500-$9000 in alternative growth light waste heat removal equipment and a 3 year payback period.
The existing system can be incorporated as a back-up to the alternate methods of heat rejection andsatisfy excess cooling demands during periods when pond water temperature is elevated and no spaceheating is required. Reduced operation of the existing chiller will also prolong its useful lifeexpectancy.
Recommended ECM’s for Greenhouse
Replacement of all Horizontal-Air Flow (HAF) type horizontal-circulating fans with “paddle” fans.Each existing “paddle” fans use 17 % less energy and provide improved airflow. An annual energysavings of 6,300 kWh and $500 will be achieved with replacement of HAF fans.
Install variable speed drive (VSD) to control the operation of the primary ventilation fan.The application of a VSD will provide better temperature/humidity control in the greenhouse than thecurrent ON/OFF system. The VSD will also contribute to decreased heating requirements byeliminating overshoot of heat/humidity removal by the present method.
Currently the water in the ponds is continually circulated by four 3 Hp. pumps. These pumps consume83,822 kWh annually at a cost of $6,856. They represent a significant amount of the overall electricalenergy consumed (17%) and of the electrical energy use in the greenhouse (28%)
There are no established parameters to determine if this circulation rate is optimal or if it could bevaried in relation to other factors. Research would be necessary to determine if the circulation ratecould be optimized to the stage of lettuce growth, rate of photosynthetic activity during dark periods,
8or during periods of high or low ambient temperatures. A VSD on these pumps would provide themethod to vary flow rates and also offer energy savings.
Even a relatively small reduction in circulation rates would produce significant savings.A 10% reduction in pond pump circulation rate would reduce kWh use by 8,300 kWh and save $685annually
Recommended ECM’s for Natural Gas Fired Boiler Operation
Supplemental space heating of the greenhouse by natural gas is the largest single energy use in thefacility. In 2002, 28,898 Therms of natural gas were used at a cost of $29,051.Space heating consumes 40% of the total energy budget. ECM’s have been identified for two areasof natural gas fired boiler control operation.
The first ECM recommends installation of modulating controls for boiler high limit temperature setpoint. This type of control automatically adjusts high limit set point temperature of the boiler tomatch variable greenhouse heating demands caused by fluctuation of ambient temperatures. Asambient temperature increases, greenhouse-heating demand decreases and boiler-operatingtemperature can be reduced. This control system allows more precise regulation of boiler watertemperature, limiting standby losses and improving overall seasonal combustion efficiency.
The second ECM proposes the application of a variable speed drive (VSD) to the boiler-loopcirculating pumps. Presently, whenever the boilers are operated two 2 hp pumps run continuouslycirculating hot water thru the boiler. The operation of these pumps consume 76% of the totalelectrical energy used in the utility room area, and 3% of all power used in the greenhouse. Operatingcosts for theses pumps is $1,396 annually with 17,076 kWh consumed.
The circulation rate of the boiler-loop circulating pumps could be significantly reduced when thegreenhouse does not require supplemental heating. The application of VSD to these pumps offers acompound energy savings. Reduction of pump speed will greatly decrease electrical energyconsumption. Reduced flow rate of boiler water will lessen standby losses and improve overall boilerefficiency. A VSD would be able to provide energy savings roughly 70% of the total time the boilersare in operation.
Excessive boiler standby losses are evidenced by greatly increased therm per degree-day rates duringtemperate periods, when greenhouse-heating demand is low. The magnitude of therms /degree-day(2.9 – 3.9 therms/degree-day) during periods of high heating loads (winter) effectively doubles duringperiods of reduced heating demands (early fall, late spring) to 4.5 – 8.3 therms/degree-day. The higherrate of heating energy used per degree day indicates that a larger amount of purchased natural gasenergy is being lost and not delivered as useful heating energy.
The combination of lowered boiler operating temperature and reduced flow thru the boiler willeffectively limit these stand-by losses.
9ANALYSIS OF ELECTRICAL ENERGY USE
A comprehensive inventory of electrical equipment was conducted at the CEA Greenhouse toestablish a basis for analyzing the flow of energy through the facility.This inventory is recorded in Table 5.
Instantaneous power consumption was recorded with a Fluke Power Meter on all four greenhousepond pumps, greenhouse circulating fans, and growth room HPS lights. Operating hours wererecorded with Pacific Science Motor Loggers for the ventilation fans and boiler circulation pumps. AMicro Data Logger was installed to monitor energy use by the growth light chiller, walk-in cooler,and record operating hours for the greenhouse HPS lighting.
This measured data was coupled with approximation of daily hours of operation to calculate energyuse by month and for each specific piece of equipment. These results are presented in Table 6 andgraphically in the following pie charts.
Electrical Energy Use by Equipment Category
CEA Greenhouse - Energy Use by Equipment Category
Heating System Pumps
4%
Pond Pumps17%
Ventilation & Circulating Fans
8%
Lighting60%
PC & Controls1%
Refrigeration Chiller, AC,
Cooler10%
Figure 1. Energy Use by Equipment Category
10
Table 2Energy Use by Equipment Category Annual kWh Annual CostLighting 31,4135 $ 25,696.25 Ventilation & Circulating Fans 39,904 $ 3,264.19 Pond Pumps 85,443 $ 6,989.20 Heating System Pumps 19,751 $ 1,615.63 Refrigeration -Chiller, AC, Walk-In Cooler 50,763 $ 4,152.45 PC & Controls 5,256 $ 429.94 Misc. 292 $ 23.89
Total 515,544 $ 42,171.54
The overall electrical energy use in the CEA Greenhouse is allocated into the major categories ofequipment in Figure 1. The estimated annual kWh consumptions and operating costs are identified inTable 2. Sixty percent of all electrical energy is consumed by the HPS lighting, 36% in thegreenhouse and 24% by the water-cooled HPS lighting in the growth chamber. The pond circulatingpumps which run continually to provide uniform water – nutrient solution to the crop is the nextlargest user of electricity at 17%. The cooling load from the water-cooled HPS growth light chiller,growth room air conditioner and walk-in cooler is responsible for the next 10% of the total use. Theremaining 13% is allocated to the ventilation and circulating fans in the growth chamber andgreenhouse (8%), the circulating pumps on the hot water boiler (4%) and PC & Controls (1%)
Electrical Energy Use by Area
CEA Greenhouse: Areas of Energy Use
Greenhouse59%
Work Area1%
Walk In Cooler1%
Utility Room4%
Growth Room35%
Figure 2. Areas of Energy Use
Figure 2 identifies the amount of electric energy used in each physical area of the CEA Greenhouse.The greenhouse area itself is the largest user of electricity, consuming 59% of the total, followed bythe growth room with 35%. The remaining 6% is divided among the utility room (4%), the walk-incooler (1%) and the work area (1%).
11
CEA Greenhouse - Energy Use in Greenhouse
Fans - Circulating10%
Lighting60%
Ventilation Fans2%
Pond Pumps28%
Figure 3. Energy Use in Greenhouse
The energy use by equipment type is further analyzed for the greenhouse in Figure 3. Thesupplemental HPS lighting in the greenhouse is the major electric energy user (60%). The pondcirculating pumps (28%) consume the next largest portion of power. It is interesting to note that eventhough the connected load of the pond pumps is only 10% of the load from the greenhouse lighting(10.3 kW vs. 99.4 kW) the continuously running pond pumps devour almost half as much energy asthe greenhouse lighting.
CEA Greenhouse - Energy Use in Growth Room
Growth Light Chiller21%
Lighting75%
Fans - Circulating1%
Air Conditioner3%
Figure 4. Energy Use in Growth Room
The energy use shown in Figure 4 for the growth room is entirely driven by the HPS water-cooledgrowth lights. The lights themselves account for three quarters of the electric consumed. The otherloads are dedicated to removing heat generated by the lamps and use the remainder. The chiller for thewater-cooled HPS growth lights runs continuously to remove heat generated by the lights. The energyuse in this area is distinct in that it operates 24 hours per day, 365 days per year with little seasonalvariation in kW.
12
CEA Greenhouse - Growth Light Chiller Load
3.8
4
4.24.4
4.6
4.8
16:05
17:05
18:05
19:05
20:05
21:05
22:05
23:05 0:0
51:0
52:0
53:0
54:0
5
March 24 to March 25, 2003
kW
Figure 5. HPS Growth Light Chiller Load
The actual use of the growth light chiller (Figure 5) was monitored to obtain an accurate analysis ofits annual kWh use. Although the operation of the chiller is critical to the operation of the HPSgrowth lights, the heat discarded is unused and offers a potential area of energy conservation. Basedon the monitored data, the growth light chiller is projected to use 38,381 kWh annually at a cost of$3,130. This represents 21% of the electricity used in the growth chamber and 7.4% of the totalelectric use
CEA Greenhouse - Walk-In Cooler Load - kW
0
0.5
1
1.5
2
2.5
11:1
5
12:1
5
13:1
5
14:1
5
15:1
5
16:1
5
17:1
5
18:1
5
19:1
5
20:1
5
21:1
5
22:1
5
23:1
5
0:15
April 2 to April 3,2003
kW
Max kW - 2.32
Min kW - 0.17
Figure 6. Walk-In Cooler Load
The actual use of the Walk-In Cooler (Figure 6) was monitored to obtain an estimate of its annualkWh use. Based on the monitored data the walk-in cooler is expected to use 6,570 kWh per year,cost $537 to operate, and comprise 1.3% of total use.
13
PURCHASED ENERGY ANALYSIS
Electricity and natural gas service is provided to the CEA Greenhouse by NYSEG. Electricity isdelivered under PSC 115, Service Class 7-1, Large General Service with Time of Use. This rateincludes an On-Peak period weekdays from 7:00 AM to 10:00 PM, when energy (kWh) and demand(kW) are billed. An Off-Peak period from 10:00 PM to 7:00 AM weekdays and all day Saturday,Sunday, and on 6 major holidays features a reduced energy charge (kWh) and no demand (kW)charge.
Natural gas is billed on NYSEG’s Gas Firm Sales Rates – PSC No. 87, Service Classification No. 2 -General Service. This rate includes all gas delivery, weather adjustments and transition surcharges.
Electrical Energy Purchased
Electrical energy provides the majority of energy needs to operate the CEA Greenhouse.In every dollar spent for energy, 60 cents go to electricity expenses. Costs per day to operate thegreenhouse have gone down from their high of $187 per day in 2000, to $115 per day in 2002. Thishas been accomplished by a reduction in annual kWh use and decreased cost per kWh. An EconomicDevelopment Incentive Rate was instituted in July of 2002 that provided a 1.5¢ per kWh ratereduction. Total electric costs are composed of three components, On-Peak Demand (kW), On-Peakenergy (kWh), and Off-Peak energy (kWh). Off-Peak Demand (kW) is metered but not billed.
The split between On and Off-Peak energy (kWh) has remained consistent over the last four years,with 40% of all kWh used On-Peak and 60 % Off-Peak. The On-Peak Demand was greatest in May2000 at 155.2 kW. Maximum On-Peak demands have dropped by 10% to 140 kW in both 2001 and2002.
Table 3 CEA Greenhouse - Summary Annual Electric Use Ave. Ave.
% On-Peak Off-Peak YEAR On-Peak Off-Peak Off Total Demand Max Min Demand M
kWh kWh Peak kWh kW kW kW kW
2002 208,160 307,200 60% 515,360 94.0 140.8 43.2 108.6 13
2001 203,120 289,600 59% 492,720 99.5 140.0 44.8 97.9 13
2000 262,080 401,600 61% 663,680 148.9 155.2 143.2 148.0 15
1999 204,160 243,930 54% 448,090 131.5 151.2 72.8 116.9 15
Total 877,520 1,242,330 59% 2,119,850
Table 4 CEA Greenhouse Total Connected Load Energy User kW LoadGrowth Chamber 26.5
Lighting 15.29Chiller 4.37Air Conditioner 6.64Fans - Circulating 0.2
Greenhouse 118.8Lighting 99.4Ventilation Fans 3.6Pumps 11.3Fans - Circulating 3.83
Utility Room 6.2Circulating Pumps - Boiler loop 3.94Circulating Pumps - Heating loop 1.47Lighting 0.46Control System 0.3
Work Area 2.2Lighting 1.01Small Appliances/Radio 0.1PC 0.3Walk In Cooler 0.75
Total Load kW 153.6
.
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
kW
CEA Greenhouse Connected Load (kW) by Area
Misc - 2.2 kW
Utility Room - 6.2kW
Growth Room - 26.5kW
Greenhouse - 118.8kW
Total Connected Load - 153.6 kW
Figure 7. CEA Greenhouse Connected Load by Area
15The Total Connected Load is compiled in Table 3 and graphed in Figure 7. The growth room andgreenhouse account for 95% of the electrical load in the facility. The total lighting load of 116 kW isdominating. Note that the maximum recorded On-Peak demand of 155 kW is slightly below the totalconnected load as shown in Table 6, indicating very little diversity of equipment operation.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
On Peak kw
Off Peak kW
0
20
40
60
80
100
120
140
160
kW
CEA Gree nhouse Demand Profile - 2002
On Peak kw Off Peak kW
Figure 8. 2002 Monthly Demand Profile
The demand profile for 2002 shown in Figure 8 indicates the load management shift to Off-Peak onlyfor greenhouse lighting that was implemented for June, July and August. By limiting the hours ofoperation for greenhouse lighting to the Off-Peak hours (10 PM to 7AM), roughly 50 kW of demandwas removed from On-Peak. This represents a substantial savings in demand (kW) charges for thosemonths and decreased energy (kWh) costs on Off-Peak. With On-Peak demand charges of $9.15 perkW, the savings amount to $1,375 for three months.
Jan Feb Mar A pr May Jun Jul A ug Sep Oct Nov Dec
On Peak
Of f Peak
136
138
140
142
144
146
148
150
152
154
156
kW
CEA Gre e nhous e De mand Profile s - 2000
On Peak OffPeak
Figure 9. 2000 Monthly Demand Profile
16The demand profile in Figure 9 for 2000 illustrates the operation of the greenhouse lighting in bothOn and Off-Peak periods for the summer months. The differential between On and Off-Peak demandis only 2-3 kW.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Off Peak
On Peak0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
kW
CEA Greenhouse Demand Profile - 1999
Off Peak On Peak
Figure 10. 1999 Monthly Demand Profile
The demand profile in Figure 10 for 1999 shows the initial start-up phases of operation when verylittle demand control or demand shifting was evident. When compared with Figure 8 for 2002, thechange due to implementation of energy management techniques is dramatic. Both On and Off-PeakkW demand has been lowered and a large portion of On-Peak demand eliminated.
17
Figure 11. 2002 Monthly On/Off-Peak kWh
The seasonal changes in kWh use are illustrated in Figures 11 & 12. Consumption has been effectivelyreduced by 148,320 kWh from 2000 to 2002. The seasonal decline during summer has beenintensified. The split between On and Off-Peak kWh usage has remained stable with 40% On and60% Off-Peak. These changes indicate an effective approach to energy management.
Figure 12. 2000 Monthly On/Off-Peak kWh
Jan Feb
Mar
Apr
May Jun Jul
Aug
Sep
Oct
Nov
Dec
Off Peak kWh
On Peak kWh0
5000100001500020000250003000035000400004500050000
kWh
CEA Greenhouse Monthly On/Off Peak kWh - 2002
Jan FebMar
AprMay Jun Jul
AugSep
OctNov
Dec
0
10000
20000
30000
40000
50000
kWh
CEA Greenhouse Monthly On/Off Peak kWh - 2000
Off Peak kWh
On Peak kWh
18Natural Gas Purchased
Table 5 CEA Greenhouse - Summary Annual Gas UseYear Total Total $$ $$/Therm $$/Day Therms Degree Therms
Therms per Day Days per DD2002 28,898.3 $29,051.19 $1.0053 $79.16 78.74 6069 4.76162001 26,089.4 $30,051.86 $1.1519 $83.48 72.47 6041 4.31872000 38,543.8 $33,634.27 $0.8726 $92.66 106.18 6669 5.77951999 20,742.1 $15,636.64 $0.7539 $39.89 52.91 6198 3.3466Total 114,273.6 $108,373.96 $0.9484 $73.13
Purchased natural gas is used entirely to satisfy space-heating needs of the greenhouse.Approximately 40 cents from every energy dollar are allocated to natural gas costs and space heating.This makes it the largest single energy cost in operating the greenhouse.
Natural gas use is driven by environmental factors affecting solar heat gain and envelope heat loss.Heat loss is influenced by the number of heating Degree-Days, that occur during the heating seasonfrom September 1 to May 30. The colder heating season of 2000 caused the greatest use of naturalgas.
DecNovOctSeptAugJulyJuneMayAprMarFebJan
2002
2001
20000
1000
2000
3000
4000
5000
6000
Therm
s
CEA Greenhouse Monthly Gas Use
2002 2001 2000
Figure 13. Monthly Natural Gas Use 2000-2002
Changes in monthly natural gas use are shown in Figure 13. Turning off the boilers forJune, July and August is clearly evident in 2002 and to a lesser extent in 2001. The summer gas use in2000 is an indication of the rather significant stand-by losses that occur. A total of 5,795 Therms at acost of $5,482 was used in the summer of 2000 that was eliminated in 2002.
19
Figure 14 serves to emphasize the increase in boiler stand-by losses that occur during non-peakheating periods. Therms per degree-day range from 2.9 - 4.1 in December, January, and February.They effectively double to 4.8 - 13.6 Therms per degree-day in the milder months of March, April,May, September, and October). This indicates that a larger amount of natural gas purchased is wastedas stand-by losses and not delivered as useful heat energy.
Figure 14. Monthly Therms per Degree Day 2000-2002
Jan Feb Mar Apr May Oct Nov Dec
2002
200120000.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
Ther
ms/
Deg
. Day
CEA Greenhouse - Therms per Degree Day
20
Table 6. Electrical Equipment InventoryCEA Greenhouse Equipment Inventory: Size and Power Num. Watts/ Total
Area Equipment Description Installed fixture Volts Amps HP kW kW
Growth Lighting Water-cooled HPS growth lights 26 600 208 2.88 15.29 2
Chamber Chiller Chiller to cool HPS growth lights 1 208 14 4.37 2
w/ 1.5 hp circulating pump, 2@ .33hp fans,
3hp refrigeration compressor
Air Conditioner A/C to condition growth room 1 208 20 6.64 3
Fans - Circulating 2 100 0.2
Greenhouse Growth Chamber - Total Load 26.5
Lighting Pond 1 - HPS growth lights 38 600 208 2.88 26.22 4
Pond 2 - HPS growth lights 34 600 208 2.88 23.46 4
Pond 3 - HPS growth lights 34 600 208 2.88 23.46 4
Pond 4 - HPS growth lights 38 600 208 2.88 26.22 4
Lighting Load 99.4
Circulating Fans Pond 2 - Paddle fans 10 100 120 1.0 2
Pond 3 - Paddle fans 10 100 120 1.0 2
Pond 4 - Paddle fans 2 100 120 0.2 2
Basket fans 12 120 120 1.4 2
Ventilation Fans Greenhouse 4 208 3.2 1 3.83
Fan Load 7.5
Pumps Pond 1-4 Circulating pumps 4 2580 208 8 3 10.3 2
Evaporative Cooling Pad Pump 1 1 0.98
Pump Load 11.3
Greenhouse Load 118.1
Utility Natural Gas Circulating Pumps - Boiler loop 2 208 2 3.92
Room Boiler Circulating Pumps - Heating loop 1 208 1.5 1.47
Pond heat Pump -Not used 1 208 0.5 0.49
Lighting - 2 @ 8ft. 2 tube Fluorescent 2 200 0.46 6.64
Control System/Computer 1 300 0.3
Work Lighting - 175watt Metal Halide 5 175 1.01
Area Computer/Control System 1 300 0.3
Small Appliances/Radio 1 100 0.1
Walk-In Cooler Refrigeration Unit / Condensor Fans 1 208 0.75 2
Misc. Load 8.796 8.79631 Motors 75% Efficient 0.98 kW/HP Total Connected Load 153.4 kW2 Based on Metered Data 3 Measured Voltage and Amperage4 HID lighting 1.15 kW input per kW Lamp rating
Electrical Equipment Inventory
21ES
TIM
ATED
DAI
LY H
OUR
S O
F O
PERA
TIO
NTo
tal
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
TOTA
L An
nual
Cos
t Eq
uipm
ent
Desc
riptio
nkW
3128
3130
3130
3131
3031
3031
kWh
@ 8
.18
cent
s/kW
Ligh
ting
Wate
r-coo
led H
PS g
rowt
h lig
hts
15.2
924
2424
2424
2424
2424
2424
2413
3940
10,9
56.3
2$
Chill
erCh
iller
to co
ol H
PS g
rowt
h lig
hts
4.37
2424
2424
2424
2424
2424
2424
3828
13,
131.
40$
w/
1.5
hp
circu
latin
g pu
mp,
2@ .3
3hp
fans
,3h
p re
frige
ratio
n co
mpr
esso
rAi
r Con
ditio
ner
A/C
to co
nditi
on g
rowt
h ro
om6.
642
58
84
259
1248
3.62
$
Fa
ns -
Circ
ulati
ng0.
224
2424
2424
2424
2424
2424
2417
5214
3.31
$
Ligh
ting
Pond
1 -
HPS
gro
wth
light
s26
.22
1211
62
12
49
1246
750
3,82
4.17
$
Pond
2 -
HPS
grow
th li
ghts
23.4
612
116
21
24
912
4182
93,
421.
63$
Po
nd 3
- HP
S gr
owth
ligh
ts23
.46
1211
62
12
49
1241
829
3,42
1.63
$
Pond
4 -
HPS
grow
th li
ghts
26.2
212
116
21
24
912
4675
03,
824.
17$
Circ
ulati
ng F
ans
Pond
2 -
Padd
le fa
ns1.
024
2424
2424
2424
2424
2424
2487
6071
6.57
$
Po
nd 3
- Pa
ddle
fans
1.0
2424
2424
2424
2424
2424
2424
8760
716.
57$
Pond
4 -
Padd
le fa
ns0.
124
2424
2424
2424
2424
2424
2487
671
.66
$
Ba
sket
fans
1.4
2424
2424
2424
2424
2424
2424
1261
41,
031.
86$
Ve
ntila
tion
Fans
Gree
nhou
se3.
831
12
46
812
128
42
171
4258
4.22
$
Pum
psPo
nd 1
-4 C
ircul
ating
pum
ps9.
5724
2424
2424
2424
2424
2424
2483
822
6,85
6.61
$
Evap
orati
ve C
oolin
g Pa
d Pu
mp
0.98
46
812
128
416
2113
2.59
$
Natu
ral G
as B
oiler
Circ
ulati
ng P
umps
- Bo
iler l
oop
2.94
2424
2424
2424
2424
1707
61,
396.
78$
Ci
rcul
ating
Pum
ps -
Heati
ng lo
op1.
4712
86
44
68
1226
7521
8.85
$
Ligh
ting
0.46
11
11
11
198
7.98
$
Cont
rol S
ystem
/Com
puter
0.3
2424
2424
2424
2424
2424
2424
2628
214.
97$
Ligh
ting
- 175
watt
Meta
l Hali
de1.
018
88
88
88
88
88
829
3824
0.35
$
Co
mpu
ter/C
ontro
l Sys
tem0.
324
2424
2424
2424
2424
2424
2426
2821
4.97
$
Sm
all A
pplia
nces
/Rad
io0.
18
88
88
88
88
88
829
223
.89
$
Re
frige
ratio
n Un
it / C
onde
nsor
Fan
s0.
7524
2424
2424
2424
2424
2424
2465
7053
7.43
$
Day/M
onth
3128
3130
3130
3131
3031
3031
Estim
ated
kWh/
D21
1720
1215
1611
2797
490
494
394
311
7313
4218
1721
1751
5544
42,1
71.5
4$
Actu
al kW
h/Da
y21
1920
8614
4512
6492
610
9687
283
610
2712
7516
6423
79
Estim
ated
kWh/
mon
th65
636
5633
847
001
3382
030
194
2712
529
243
2924
335
181
4161
154
515
6563
651
5544
42,1
71.5
4$
Purc
hase
d kW
h/m
onth
6568
058
400
4480
037
920
2872
032
880
2704
025
920
3080
039
520
4992
073
760
5153
6042
,156
.45
$
-2
002
Misc
./Una
ccou
nted
kW
h44
2062
-220
141
00-1
474
5755
-220
3-3
323
-438
1-2
091
-459
581
24-1
84(1
5.09
)$
Table 7 Estimated Energy Use by Equipment Type, Monthly
22
Table 8 CEA Greenhouse - Electric Energy Purchased - Jan. 1999 to Jan. 2003read date # days on kWh on kW off kWh off kW total kWh kWh/dayad factor total $ $/day $/kWh01/24/03 32 25360 140.8 47200 138.4 72560 2267.5 0.67 5,360.55$ $167.52 $0.07412/23/02 32 26160 140.8 47600 138.4 73760 2305.0 0.68 4,689.09$ $146.53 $0.06411/21/02 30 20800 106.4 29120 108.0 49920 1664.0 0.65 3,402.68$ $113.42 $0.06810/22/02 29 17600 100.8 21920 97.6 39520 1362.8 0.56 2,924.03$ $100.83 $0.07409/23/02 31 10560 98.4 20240 98.4 30800 993.5 0.42 2,415.38$ $77.92 $0.07808/23/02 29 11200 46.4 14720 101.6 25920 893.8 0.80 1,684.39$ $58.08 $0.065
07/25/02 ** 10 4720 45.6 4960 99.2 9680 968.0 0.88 619.08$ $61.91 $0.06407/15/02 20 7040 43.2 10320 91.2 17360 868.0 0.84 1,352.25$ $67.61 $0.07806/25/02 32 12880 47.2 20000 92.0 32880 1027.5 0.91 2,460.00$ $76.88 $0.07505/24/02 29 12000 88.0 16720 87.2 28720 990.3 0.47 2,715.92$ $93.65 $0.09504/25/02 30 17040 124.0 20880 123.2 37920 1264.0 0.42 3,707.98$ $123.60 $0.09803/26/02 29 16240 127.2 28560 125.6 44800 1544.8 0.51 4,118.89$ $142.03 $0.09202/25/02 32 26080 128.0 32320 125.6 58400 1825.0 0.59 5,843.05$ $182.60 $0.10001/24/02 34 25840 125.6 39840 123.2 65680 1931.8 0.64 6,242.60$ $183.61 $0.09512/21/01 31 22240 127.2 30640 122.4 52880 1705.8 0.56 5,385.28$ $173.72 $0.10211/20/01 33 18160 91.2 21920 88.8 40080 1214.5 0.55 4,066.62$ $123.23 $0.10110/18/01 28 10560 67.2 13120 63.2 23680 845.7 0.52 2,559.25$ $91.40 $0.10809/20/01 29 11520 44.8 14240 43.2 25760 888.3 0.83 2,451.82$ $84.55 $0.09508/22/01 28 12320 49.6 17120 48.0 29440 1051.4 0.88 2,827.46$ $100.98 $0.09607/25/01 30 13120 49.6 17120 48.0 30240 1008.0 0.85 2,827.46$ $94.25 $0.09406/25/01 33 14720 123.2 23680 125.6 38400 1163.6 0.39 4,229.64$ $128.17 $0.11005/23/01 29 14240 124.8 19200 124.0 33440 1153.1 0.38 3,936.99$ $135.76 $0.11804/24/01 29 15680 129.6 24080 128.8 39760 1371.0 0.44 4,417.12$ $152.31 $0.11103/26/01 31 19040 129.6 34240 128.8 53280 1718.7 0.55 5,308.74$ $171.25 $0.10002/23/01 29 25760 140.0 36960 138.4 62720 2162.8 0.64 6,126.80$ $211.27 $0.09801/25/01 30 25760 116.8 37280 116.0 63040 2101.3 0.75 5,873.15$ $195.77 $0.09312/26/00 34 26240 147.2 40560 146.4 66800 1964.7 0.56 6,463.03$ $190.09 $0.09711/22/00 33 26640 147.2 41680 147.2 68320 2070.3 0.59 6,564.05$ $198.91 $0.09610/20/00 28 23360 149.6 30880 148.8 54240 1937.1 0.54 5,670.38$ $202.51 $0.10509/22/00 30 15200 144.8 24240 145.6 39440 1314.7 0.38 4,491.41$ $149.71 $0.114
VI. Tabulation of Energy Purchased - Electric and Natural Gas (provided by NYSEG)
23
Table 8 cont.read date # days on kWh on kW off kWh off kW total kWh kWh/dayad factor total $ $/day $/kWh
08/23/00 29 14560 143.2 23920 146.4 38480 1326.9 0.39 4,396.20$ $151.59 $0.114
07/25/00 32 15840 148.8 27920 146.4 43760 1367.5 0.38 4,809.20$ $150.29 $0.110
06/23/00 30 18320 151.2 27600 148.8 45920 1530.7 0.42 5,043.26$ $168.11 $0.110
05/24/00 29 17520 155.2 28960 150.4 46480 1602.8 0.43 5,096.50$ $175.74 $0.110
04/25/00 32 24640 149.6 39520 149.6 64160 2005.0 0.56 6,286.22$ $196.44 $0.098
03/24/00 25 19440 152.0 27920 147.2 47360 1894.4 0.52 5,171.71$ $206.87 $0.109
02/28/00 32 27920 149.6 41440 150.4 69360 2167.5 0.60 6,689.13$ $209.04 $0.096
01/27/00 29 32400 148.8 46960 148.8 79360 2736.6 0.77 7,404.59$ $255.33 $0.093
12/29/99 30 30560 148.8 34000 148.0 64560 2152.0 0.60 6,488.08$ $216.27 $0.100
11/29/99 38 38000 142.8 65840 148.8 103840 2732.6 0.80 9,455.15$ $248.82 $0.091
10/22/99 28 22240 151.2 28400 151.2 50640 1808.6 0.50 5,481.76$ $195.78 $0.108
09/24/99 30 23600 148.0 23520 148.0 47120 1570.7 0.44 5,283.33$ $176.11 $0.112
08/25/99 29 19840 148.0 21290 146.4 41130 1418.3 0.40 5,481.76$ $189.03 $0.133
07/27/99 29 18800 150.4 18720 147.2 37520 1293.8 0.36 5,283.33$ $182.18 $0.141
06/28/99 33 17920 141.6 19840 136.8 37760 1144.2 0.34 4,475.03$ $135.61 $0.119
05/26/99 29 15360 140.8 16720 140.0 32080 1106.2 0.33 4,050.15$ $139.66 $0.126
04/27/99 29 9760 72.8 10560 48.0 20320 700.7 0.40 2,376.21$ $81.94 $0.117
03/29/99 33 2400 116.8 2080 103.2 4480 135.8 0.05 1,730.62$ $52.44 $0.386
02/24/99 28 1840 105.6 1760 7.2 3600 128.6 0.05 1,528.46$ $54.59 $0.425
01/27/99 19 3840 111.2 1200 77.6 5040 265.3 0.10 1,258.55$ $66.24 $0.250
01/08/99 52 6720 119.2 3360 11.2 10080 193.8 0.07 3,504.57$ $67.40 $0.348
11/17/98 39 3440 105.6 0 98.4 3440 88.2 0.03 1,866.63$ $47.86 $0.543
10/09/98 87 2240 112.8 480 5.6 2720 31.3 0.01 3,930.92$ $45.18 $1.445
** First bill with account in Cornell University 227,826.45$ * based on peak Kw & total Kwh.
24
Table 9 CEA Greenhouse - Natural Gas Purchased - Jan. 1999 to Jan. 2002 (provided by NYSEG)read date # of days therms thm/day Degree Day thms/dd total $ $/day $/therm01/24/03 32 4714 147.31 1371 3.4 $3,730.56 $116.58 $0.7912/23/02 32 3965.6 123.93 1163 3.4 $3,232.67 $101.02 $0.8211/21/02 30 2908.4 96.95 753 3.9 $2,663.88 $88.80 $0.9210/22/02 29 1627.3 56.11 318 5.1 $1,470.68 $50.71 $0.9009/23/02 31 385.4 12.43 -43 -9.0 $394.13 $12.71 $1.0208/23/02 29 9.1 0.31 $25.06 $0.86 $2.75
07/25/02 ** 10 4 0.40 $9.36 $0.94 $2.3407/15/02 20 16.2 0.81 $30.38 $1.52 $1.8806/25/02 32 1496.9 46.78 $1,651.30 $51.60 $1.1005/24/02 29 2918.8 100.65 444 6.6 $3,120.97 $107.62 $1.0704/25/02 30 3232.9 107.76 492 6.6 $3,444.36 $114.81 $1.0703/26/02 29 3918.1 135.11 870 4.5 $4,149.28 $143.08 $1.0602/25/02 32 3824.7 119.52 994 3.8 $4,035.85 $126.12 $1.0601/24/02 34 4590.9 135.03 1184 3.9 $4,823.27 $141.86 $1.0512/21/01 31 2843.4 91.72 679 4.2 $3,027.36 $97.66 $1.0611/20/01 33 2682.4 81.28 667 4.0 $2,864.25 $86.80 $1.0710/18/01 28 2200.8 78.60 266 8.3 $2,371.51 $84.70 $1.0809/20/01 29 896.7 30.92 55 16.3 $1,028.59 $35.47 $1.1508/22/01 28 117.2 4.19 $157.22 $5.62 $1.3407/25/01 29 490.1 16.90 $608.13 $20.97 $1.2406/26/01 33 1218.6 36.93 $1,360.08 $41.21 $1.1205/24/01 29 1489.8 51.37 201 7.4 $1,640.40 $56.57 $1.1004/25/01 29 2584.3 89.11 553 4.7 $2,746.78 $94.72 $1.0603/27/01 32 4240.9 132.53 1134 3.7 $4,558.32 $142.45 $1.0702/23/01 29 3742.6 129.06 1061 3.5 $4,908.42 $169.26 $1.3101/25/01 30 3582.6 119.42 1218 2.9 $4,780.80 $159.36 $1.3312/26/00 34 4757.8 139.94 1344 3.5 $4,989.93 $146.76 $1.0511/22/00 33 2783 84.33 741 3.8 $2,849.61 $86.35 $1.0210/20/00 28 1779.9 63.57 1021 1.7 $1,851.99 $66.14 $1.0409/22/00 30 2006.9 66.90 32 62.7 $1,921.59 $64.05 $0.96
25Table 9 cont.
read date # of days therms thm/day Degree Day thms/dd total $ $/day $/therm
08/23/00 29 1957.1 67.49 $1,855.21 $63.97 $0.95
07/25/00 32 1788.5 55.89 $1,753.58 $54.80 $0.98
06/23/00 30 2049.9 68.33 47 43.6 $1,872.96 $62.43 $0.91
05/24/00 29 2934.2 101.18 216 13.6 $2,424.71 $83.61 $0.83
04/25/00 32 3803.6 118.86 654 5.8 $3,014.71 $94.21 $0.79
03/24/00 25 3739.5 149.58 642 5.8 $2,903.81 $116.15 $0.78
02/28/00 32 5954 186.06 1230 4.8 $4,510.56 $140.96 $0.76
01/27/00 29 4989.4 172.05 1226 4.1 $3,685.61 $127.09 $0.74
12/29/99 30 3278.3 109.28 999 3.3 $2,489.45 $82.98 $0.76
11/29/99 38 1357.5 35.72 716 1.9 $1,192.07 $31.37 $0.88
10/22/99 28 633.1 22.61 359 1.8 $587.82 $20.99 $0.93
09/24/99 30 301.0 10.03 21 14.3 $300.41 $10.01 $1.00
08/25/99 29 88.8 3.06 $97.75 $3.37 $1.10
07/27/99 29 191.6 6.61 $187.81 $6.48 $0.98
06/28/99 33 661.2 20.04 0 0.0 $580.17 $17.58 $0.88
05/26/99 29 1153.4 39.77 173 6.7 $924.51 $31.88 $0.80
04/27/99 28 1589.4 56.76 544 2.9 $1,174.09 $41.93 $0.74
03/30/99 34 3810.5 112.07 1174 3.2 $2,594.33 $76.30 $0.68
02/24/99 33 3654.4 110.74 1166 3.1 $2,530.64 $76.69 $0.69
01/22/99 51 4022.9 78.88 2560 1.6 $2,977.59 $58.38 $0.74
11/07/98 38 490.2 12.90 $532.16 $14.00 $1.09
** First bill with account in Cornell University $112,637
26Appendix A – CEA Greenhouse Monitored Load/Use Data Natural Gas Equipment
Natural Gas Boilers - 2Mfg. - Teledyne LarsInput Btu. / Hr. – 1,200,000Output Btu. / Hr. – 972,000
Date Equipment3/24/2003 Pond Pumps 1 2 3 4
kW A Ph 0.89 0.93 0.85 0.90kW B Ph 0.90 0.91 0.75 0.78kW C Ph 0.80 0.84 0.85 0.90Total kW 2.59 2.68 2.45 2.58 Ave kW 2.58PF 0.92 0.94 0.91 0.91
3/25/2003 Boiler Loop Pumps - run 24/7 kWPond 2 -10 Circulating Paddle Fans 0.98Pond 3 -10 Circulating Paddle Fans 0.96Pond 4 -2 Circulating Paddle Fans 0.2Pond 4 -12 Circulating Basket Fans 1.4
Total Circulating Fans 3.54
Growth Room LightsCircuit 1 2.56Circuit 2 2.66Circuit 3 2.51Circuit 4 3.25Circuit 5 1.85Circuit 6 2.46Total 15.29 kW
Electric Load/Use Monitoring Equipment used:
Fluke 39 Power Meter - instantaneous power (kW) of pond pumps, growth room lights, paddle fans and ventilation fans.
Micro Data Logger – portable data acquisition system- with WattNode watt hour transducer and Pulse Counter for kW and
kWh measurements of walkin-cooler & growth light chiller- Status AC/DC voltage module to measure percent “On” time of
greenhouse lights & ventilation fans.Pacific Science & Technology – Motor Logger – measure operating hours for
- boiler loop pumps, greenhouse heating loop circulator pumps.
27
Ventilation Fan - Greenhouse 35.9 hrs. run time from 362 hrs3/24 @ 15:45 to 4/8 @ 10:15 - 15 days, 1.5 hrs
8.62 Hrs / day10% % On Time
Chiller for Growth Lights 4.37 kW
Circulator Pump - Greenhouse 126.1 hrs run time from 193 hrsHeating Loop 3/25 @ 8:45 to 4/2 @ 10:00 - 8days, 1hr.
15.7 Hrs / day65% Percent On Time
Ventilation Fan - Greenhouse 23.3 hrs. run time from 210 hrs3/24 @ 15:45 to 4/2 @ 10:00 - 8 days, 18 hrs
2.66 Hrs / day4/8/2003 11% % On TimeCirculator Pump - Greenhouse 229.8 hrs run time from 319 hrs
Heating Loop 3/25 @ 8:45 to 4/8 @ 10:15 - 13 days, 6.5 hr.55.2 Hrs / day72% Percent On Time
4/2/2003
28Walk-In Cooler Measured UseDate kWh
April 3, 2003 20.6255
April 4, 2003 17.8275
April 5, 2003 18.3105
April 6, 2003 15.7185
April 7, 2003 20.093
Total - 5 Days 92.575Ave kW 0.771kWh / Day 18.52Annual kWh 6758
Growth Light Chiller Measured Use Date KWh/Day
March 25, 2003 108.43
March 26, 2003 100.97
March 27, 2003 101.22
March 28, 2003 106.23
March 29, 2003 105.95
March 30, 2003 105.95
Total - 6 Days 628.74Ave kW 4.37kWh / Day 104.79Annual kWh 38248
29
Greenhouse Lights - Total Hrs OperationFrom 3/24/03 @ 16:05To 3/31/03 @ 15:50
168.25 Total Hrs. 54.97 Hrs On 33%7.0 Days 7.8 hrs/day
Off-Peak Use 3/28/03 @ 22:00to 3/31/03 @ 7:00
56.75 Total Hrs. 31.97 Hrs On 56%2.36 Days 13.5 hrs/day
From 4/2/03 @ 10:45To 4/8/03 @ 12:00
144.5 Total Hrs. 73.57 Hrs On 51%6.0 Days 12.2 hrs/day
Off-Peak Use 4/4/03 @ 22:00to 4/7/03 @ 7:00
56 Total Hrs. 24.21 Hrs On 43%2.3 Days 10.4 hrs/day