NetZero Greenhouse Project

Transcription

1 NetZero Greenhouse Project Abigail Clarke-Sather May 30, 2012

2 To provide economic, environmental, and social benefits to economically disadvantaged individuals and communi7es; and to provide educa7on and training that builds local capacity. Environment Stewardship Social Responsibility Economic Viability

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4 Colorado Dept of Agriculture ACRE grant Purpose Ø Energy prices and new construc2on costs are high Goal Ø Design, model, and test energy efficiency retrofits Deliverables Ø Interview stakeholders Ø Review current best prac2ces Ø Research exis2ng energy efficient greenhouses Ø Analyze data used to drive greenhouse design Ø Modeling poten2al energy efficiency solu2ons Ø Install energy conserva2on measures and assess impact

5 What is it? In Colorado, heagng greenhouses is the main energy expenditure over the year Ø Cooling costs are less than hea2ng costs The basic strategies to retrofit greenhouses to be more energy efficient include: Ø Reducing greenhouse heat losses Ø Increasing efficiency of hea2ng systems Ø Employing thermal buffers

6 Energy ConservaGon Measures (ECMs) Examples Considered Ø Wall insula2on Ø Increase unit heater efficiency Ø Triple layer polycarbonate glazing Ø Energy curtain Ø Founda2on Insula2on Ø Internal thermal mass Renewable Energy Examples Considered Ø Geothermal heat pumps Ø Solar thermal panels (air and water)

7 Topics Covered Computer Modeling of ECMs Modeling and EsGmates for Renewable Energy Installed Trials and Energy Impacts Conclusions RecommendaGons

8 Three Greenhouses Modeled Small Ø CSU, Quonset Shape Ø 972 Square feet Medium Ø CSU Ø 10,534 square feet Large Ø Fort Collins Ø 85,796 square feet

9 Gas consumption (MMBtu) HeaGng Energy Use Natural Gas Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Actual equest

10 Electricity consumption (kwh) 1000 Electricity Use Actual equest

11 Small Greenhouse Increasing Furnace Energy Efficiency to 93% Ø Hea2ng Savings of 20.06%, Payback in years Thermal Mass 34 Water Barrels Ø Hea2ng Savings of 16.0%, Payback in 2.25 years Triple Polycarbonate Glazing 16 mm Ø Hea2ng Savings of 13.89%, Payback in years Energy Curtain Ø Hea2ng Savings of 13.33%, Payback in years Wall InsulaGon R- 13 Ø Hea2ng Savings of 9.49%, Payback in years

12 Small Greenhouse Energy savings in the short term Over long term loss in heat pump efficiency Fort Collins is too cold to make these work long term Costs based on bored feet Ø Payback period between 18.8 and 254 years Costs based on $1000 per ton system needed Ø Payback period between 4.93 and 4.97 years

13 Small Greenhouse Concerns Ø Area needed for system Ø Size of system needed to offset hea2ng load Ø Cost of panels Solar hot air Ø Payback period greater than 100 years! Solar hot water Ø Payback period from 12 to over 100 years Other solar thermal opgons make more sense Ø Thermal mass Ø Phase- changing materials

14 Two Small Greenhouses CSU, Fort Collins One experimental, one control greenhouse Implemented solugons Ø Insula2on R- factor 6 on boaom 3 feet of wall Ø Thermal Mass thirty- four 55 gallon water filled plas2c drums Ø Phase- changing materials four pipes of salt hydrates plus a pump and ven2ng system to move heat

15 Two Small Greenhouses CSU, Fort Collins One experimental, one control greenhouse Implemented solugons Ø Insula2on R- factor 6 on boaom 3 feet of wall Ø Thermal Mass thirty- four 55 gallon water filled plas2c drums Ø Phase- changing materials four pipes of salt hydrates plus a pump and ven2ng system to move heat

16 East and West Greenhouses at PERC faciliges

17 East and West Greenhouses at PERC faciliges

18 East and West Greenhouses at PERC faciliges

19 Small Greenhouse Annual HeaGng Energy = 24*f*BLC*DDh/η Ø η= efficiency of hea2ng equipment (i.e. furnace efficiency, assumed to be 75% efficient) Ø BLC = Building Load Coefficient Ø DDh = hea2ng degree days (the cutoff temperature for hea2ng degree days considered was 65 degrees Fahrenheit) Ø f = % of how much of the day hea2ng occurs, for this work assumed 24 hours/day so f=1 Ø Note: All hea2ng degree day informa2on came from the Western Regional Climate Center for Fort Collins hap://

20 InsulaGon Experiment Therm usage over period Experimental Greenhouse (East) Average Temperature (F) over period y = x R² = Insulation Linear (Insulation)

21 Small Greenhouses Electricity Use had anomalies Ø Impossible to determine energy use Ø Electricity use not necessarily connected to outside temperature Natural Gas use showed energy savings

22 Natural Gas Use Thermal Mass and InsulaGon Ø Payback period less than 1 year! Phase- Change Material costs unknown

23 Simple SoluGons = Big Savings Low investment in energy efficiency can result in large energy savings InsulaGon and Thermal Mass are good ways to save energy and energy costs Real savings may differ from trial solugons Geothermal heat pumps and Solar thermal panels don t make sense in Fort Collins Other solar thermal opgons thermal mass and phase- changing materials beier opgons Over long term loss in heat pump efficiency

24 QuesGons?

25 NetZero Greenhouse Project Abigail Clarke-Sather May 30, 2012