poste ENERGY-EFFICIENT WATER HEATING SYSTEM FOR ...
ENERGY-EFFICIENT WATER HEATING SYSTEM
FOR EXISTING BUILDINGS 2010-2011 Energy-Efficient Building Technologies Challenge Jonathan Bumstead, Jeffrey Fein, Patrick Musgrave
PRODUCT DESCRIPTION The proposed product is an energy-efficient water-heating system that consists of a solar water heater and a greywater heat exchanger that can easily be implemented as an adjunct to heating systems in existing buildings. Two different solar water heaters were constructed in order to compare the efficacy versus construction cost of this component of the system.
ENERGY AND COST SAVINGS
WINDOW ENCLOSURE DESIGN This water heater was designed for colder climates. An array of black ABS pipes rest inside an insulated window frame angled 40Β° from the ground and holds 23.3L of water. New water circulates through from a reservoir every half hour via a timed pump.
REUSED BOTTLE DESIGN The reused bottle design was constructed for warmer climates. Reused plastic bottles are glued together, housing 40 ft. of black polyethylene tubing that holds 1.5L of water at any given time.
πππ ππππ ππ ππ π πππ¦
Energy used to heat water using nonrenewable resources (GWh)
Energy saved using water heating system (GWh)
Residential
492.1
246.1
Commercial
212.2
106.1
Total
704.3
352.2
β #ππ ππππππ ππ βππ’π π β 365 β βπ
Potential Thermal thermal energy energy savings with savings 50% after one efficient year system after (kWh) one year (kWh) High 13,600 6,800 Low 492 246 Average 6,554 3,277
Cost Savings after Cost saving after one year with 50% two years with heated by 50% heated by proposed proposed system system(USD) (USD) Electric Natural Electric Natural Gas Gas 778.60 28.17 375.22
451.52 16.33 217.59
1557.20 56.33 750.43
903.04 32.67 435.19
Table 5: Energy saved heating water annually in U.S. if water heating system implemented in all existing buildings
ACKNOWLEDMENTS We would like to thank William Clark for being our advisor along with John Metzger and John Leonard for advice regarding theoretical questions. Funding was provided by the Mascaro Center for Sustainable Innovation. In addition, we would like to thank the inhabitants of 235 N. Neville Ext. for use of their house; and the parents of Patrick Musgrave, for the use of their vehicles.
REFERENCES 1 EIA,
It was assumed that the proposed water heating system including the heat exchanger was capable of heating 50% of the hot water demand because solar water heaters alone can heat, on average in the United States, 50% of the hot water required in a building1.
Both solar water heaters constructed were tested by heating water for one hour on a sunny day with an average outside temperature of 47Β°F. The initial and final temperatures of the water measured and resulting energy absorbed by the water are shown in table 1. Volume Cost Initial Final Energy Power of (USD) Temperature Temperature absorbed (W) water (Β°F) (Β°F) by water (liters) (MJ) Window Enclosure Reused Bottle
www.PosterPresentations.com
πππ π ππ βππ‘ π€ππ‘ππ π’π ππ
Table 2. Calculation of potential money and thermal energy savings for heating water by electricity in five person household
COMPARISON OF SOLAR WATER HEATERS
RESEARCH POSTER PRESENTATION DESIGN Β© 2011
Table 4 shows the energy that could be saved annually in the United States assuming the proposed water system could heat 50% of the hot water demand. The total energy saved amounts to 253,000 tons of CO2.
(Equation 1)
Using data from Table 1 and Equation 1, the projected energy savings for a five person household were calculated and are displayed in Table 2:
THE PROPOSED SYSTEM
Fig 1.Schematic of the water-heating system. The dashed line outlines the proposed addition to the existing system
π = π β π β βπ
where π is the energy to heat the water, π is the mass of water, βπ is the change in temperature, and π is the specific heat of water.
The solar water heater acts as a greenhouse. The sunβs radiation passes through a glass or plastic window and heats the surface of the pipes. This heat is conducted to the water inside. As well, the air above the pipes is heated through convection. The window prevents this heated air from escaping. The inside of the enclosure is black to better absorb radiation. Most of the radiation reflected from the inside of the enclosure is low wavelength and cannot pass through the glass back to the outside.
The following description and Fig. 1 explain the proposed water heating system: β’ (1 to 2) Cold water flows from the public source through a heat exchanger β’ (8 to 9) Heat is transferred from outgoing hot greywater to incoming cold water β’ (2) Partially heated water flows into an insulated tank β’ (3 to 4) Pump intermittently circulates water from tank β’ (4) Water flows from tank to solar water heater and pump is shut off β’ (4 to 5) After 30min, pump circulates more water from tank into heater and heated water reenters the tank before deactivation of pump β’ Continuation of cycle to heat all water inside the tank β’ (6) Water flows from insulated tank into a conventional water heater for storage and additional heating if required β’ (7) Water exits conventional heater as required by user β’ (8 to 9) Greywater passes through heat exchanger and exits building
Equation 1 was used to estimate the potential thermal energy required to heat the amount of hot water used in a residential house in one year:
=πβ
BACKGROUND
ENVIRONMENTAL IMPACT
23.3
323.87
34
74
2.17
602.01
1.54
74.02
34
100
0.24
65.66
Table 1. Energy and cost comparison of solar water heaters based on preliminary tests.
Window enclosure solar water heater with installation Reused bottle solar water heater with installation Window enclosure solar water heater with heat exchanger Reused bottle solar water heater with heat exchanger
Cost (USD)
Payback time for electric (years)
Payback time for natural gas (years)
454.01
1.21
2.09
204.16
0.54
0.94
754.01
2.01
3.47
504.16
1.34
2.32
Table 3. Cost of construction and implementation of several configurations of the proposed water heating systems and their payback time for a five person household
A Look at Residential Energy Consumption in 2005, October 2008, Table US-14. 2 Denholm, P.."The Technical Potential of Solar Water Heating to Reduce Fossil Fuel Use and Greenhouse Gas Emissions in the United States."National Renewable Energy Laboratory. Mar 2007. U.S. Department of Energy.Accessed: 23 July 2009 . 3 βWater Heaters.βConsumer Energy Center, California Energy Commission. August 2010. http://www.consumerenergycenter.org/home/appliances/waterheaters.ht ml. 4 Fairey, Philip & Parker, Danny. βA Review of Hot Water Draw Profiles Used in Performance Analysis of Residential Domestic Hot Water Systems.β 5 βHot Water Consumption per Occupant.βThe Engineering Toolbox. 2007. http://www.engineeringtoolbox.com/hot-water-consumption-persond_91.html 6βAverage Retail Price of Electricity to Ultimate Customers by End-Use Sector.βU.S. Energy Information Administration. July 2010. http://www.eia.doe.gov/electricity/epm/table5_6_b.html 7 βNatural Gas Prices.β U.S. Energy Information Administration: Independent Statistics and Analysis. 29 September. 2010. Web. 24 October 2010.
FOR EXISTING BUILDINGS 2010-2011 Energy-Efficient Building Technologies Challenge Jonathan Bumstead, Jeffrey Fein, Patrick Musgrave
PRODUCT DESCRIPTION The proposed product is an energy-efficient water-heating system that consists of a solar water heater and a greywater heat exchanger that can easily be implemented as an adjunct to heating systems in existing buildings. Two different solar water heaters were constructed in order to compare the efficacy versus construction cost of this component of the system.
ENERGY AND COST SAVINGS
WINDOW ENCLOSURE DESIGN This water heater was designed for colder climates. An array of black ABS pipes rest inside an insulated window frame angled 40Β° from the ground and holds 23.3L of water. New water circulates through from a reservoir every half hour via a timed pump.
REUSED BOTTLE DESIGN The reused bottle design was constructed for warmer climates. Reused plastic bottles are glued together, housing 40 ft. of black polyethylene tubing that holds 1.5L of water at any given time.
πππ ππππ ππ ππ π πππ¦
Energy used to heat water using nonrenewable resources (GWh)
Energy saved using water heating system (GWh)
Residential
492.1
246.1
Commercial
212.2
106.1
Total
704.3
352.2
β #ππ ππππππ ππ βππ’π π β 365 β βπ
Potential Thermal thermal energy energy savings with savings 50% after one efficient year system after (kWh) one year (kWh) High 13,600 6,800 Low 492 246 Average 6,554 3,277
Cost Savings after Cost saving after one year with 50% two years with heated by 50% heated by proposed proposed system system(USD) (USD) Electric Natural Electric Natural Gas Gas 778.60 28.17 375.22
451.52 16.33 217.59
1557.20 56.33 750.43
903.04 32.67 435.19
Table 5: Energy saved heating water annually in U.S. if water heating system implemented in all existing buildings
ACKNOWLEDMENTS We would like to thank William Clark for being our advisor along with John Metzger and John Leonard for advice regarding theoretical questions. Funding was provided by the Mascaro Center for Sustainable Innovation. In addition, we would like to thank the inhabitants of 235 N. Neville Ext. for use of their house; and the parents of Patrick Musgrave, for the use of their vehicles.
REFERENCES 1 EIA,
It was assumed that the proposed water heating system including the heat exchanger was capable of heating 50% of the hot water demand because solar water heaters alone can heat, on average in the United States, 50% of the hot water required in a building1.
Both solar water heaters constructed were tested by heating water for one hour on a sunny day with an average outside temperature of 47Β°F. The initial and final temperatures of the water measured and resulting energy absorbed by the water are shown in table 1. Volume Cost Initial Final Energy Power of (USD) Temperature Temperature absorbed (W) water (Β°F) (Β°F) by water (liters) (MJ) Window Enclosure Reused Bottle
www.PosterPresentations.com
πππ π ππ βππ‘ π€ππ‘ππ π’π ππ
Table 2. Calculation of potential money and thermal energy savings for heating water by electricity in five person household
COMPARISON OF SOLAR WATER HEATERS
RESEARCH POSTER PRESENTATION DESIGN Β© 2011
Table 4 shows the energy that could be saved annually in the United States assuming the proposed water system could heat 50% of the hot water demand. The total energy saved amounts to 253,000 tons of CO2.
(Equation 1)
Using data from Table 1 and Equation 1, the projected energy savings for a five person household were calculated and are displayed in Table 2:
THE PROPOSED SYSTEM
Fig 1.Schematic of the water-heating system. The dashed line outlines the proposed addition to the existing system
π = π β π β βπ
where π is the energy to heat the water, π is the mass of water, βπ is the change in temperature, and π is the specific heat of water.
The solar water heater acts as a greenhouse. The sunβs radiation passes through a glass or plastic window and heats the surface of the pipes. This heat is conducted to the water inside. As well, the air above the pipes is heated through convection. The window prevents this heated air from escaping. The inside of the enclosure is black to better absorb radiation. Most of the radiation reflected from the inside of the enclosure is low wavelength and cannot pass through the glass back to the outside.
The following description and Fig. 1 explain the proposed water heating system: β’ (1 to 2) Cold water flows from the public source through a heat exchanger β’ (8 to 9) Heat is transferred from outgoing hot greywater to incoming cold water β’ (2) Partially heated water flows into an insulated tank β’ (3 to 4) Pump intermittently circulates water from tank β’ (4) Water flows from tank to solar water heater and pump is shut off β’ (4 to 5) After 30min, pump circulates more water from tank into heater and heated water reenters the tank before deactivation of pump β’ Continuation of cycle to heat all water inside the tank β’ (6) Water flows from insulated tank into a conventional water heater for storage and additional heating if required β’ (7) Water exits conventional heater as required by user β’ (8 to 9) Greywater passes through heat exchanger and exits building
Equation 1 was used to estimate the potential thermal energy required to heat the amount of hot water used in a residential house in one year:
=πβ
BACKGROUND
ENVIRONMENTAL IMPACT
23.3
323.87
34
74
2.17
602.01
1.54
74.02
34
100
0.24
65.66
Table 1. Energy and cost comparison of solar water heaters based on preliminary tests.
Window enclosure solar water heater with installation Reused bottle solar water heater with installation Window enclosure solar water heater with heat exchanger Reused bottle solar water heater with heat exchanger
Cost (USD)
Payback time for electric (years)
Payback time for natural gas (years)
454.01
1.21
2.09
204.16
0.54
0.94
754.01
2.01
3.47
504.16
1.34
2.32
Table 3. Cost of construction and implementation of several configurations of the proposed water heating systems and their payback time for a five person household
A Look at Residential Energy Consumption in 2005, October 2008, Table US-14. 2 Denholm, P.."The Technical Potential of Solar Water Heating to Reduce Fossil Fuel Use and Greenhouse Gas Emissions in the United States."National Renewable Energy Laboratory. Mar 2007. U.S. Department of Energy.Accessed: 23 July 2009 . 3 βWater Heaters.βConsumer Energy Center, California Energy Commission. August 2010. http://www.consumerenergycenter.org/home/appliances/waterheaters.ht ml. 4 Fairey, Philip & Parker, Danny. βA Review of Hot Water Draw Profiles Used in Performance Analysis of Residential Domestic Hot Water Systems.β 5 βHot Water Consumption per Occupant.βThe Engineering Toolbox. 2007. http://www.engineeringtoolbox.com/hot-water-consumption-persond_91.html 6βAverage Retail Price of Electricity to Ultimate Customers by End-Use Sector.βU.S. Energy Information Administration. July 2010. http://www.eia.doe.gov/electricity/epm/table5_6_b.html 7 βNatural Gas Prices.β U.S. Energy Information Administration: Independent Statistics and Analysis. 29 September. 2010. Web. 24 October 2010.
