MSc. Sustainable Energy & Green Technologies University College Dublin, Ireland
BSEN40330 Energy Systems and Sustainable Environment Assignment 2: Improving the Energy Profile of a Domestic Dwelling Using Renewable Energy Systems
Name: Aisling Ni Cheallaigh Student ID: 06452825 Date: 11/11/2010
Table of Contents
1 2 Introduction …………………………………………………………………………………………………………………… 2 Renewable Energy Systems ……………………………………………………………………………………………… 3 2.1 2.2 3 Renewable Energy Options in Ireland …………………………………………………………………………. 3 Renewable Energy Grants …………………………………………………………………………………………. 4
Improving the Energy Profile of a Domestic Dwelling using Renewable Energy Systems ………….. 5 3.1 Scenario 1: Installing a Heat Pump in a Domestic Dwelling……………………………………………. 5 Types of Heat Pumps ………………………………………………………………………………………… 5 How Heat Pumps Work ……………………………………………………………………………………… 6 Benefits of Heat Pumps……………………………………………………………………………………… 7 Cost Savings of a Heat Pump versus an Oil Burner ………………………………………………… 7
The Term Paper on Heat Pump
Outdoor components of a residential air-source heat pump A heat pump is a machine or device that transfers thermal energy from one location, called the “source,” which is at a lower temperature, to another location called the “sink” or “heat sink”, which is at a higher temperature. Thus, heat pumps moves thermal energy opposite to the direction that it normally ...
3.1.1 3.1.2 3.1.3 3.1.4 3.2
Scenario 2: Installing a Solar Thermal System ……………………………………………………………… 9 Types of Solar Panel heating system …………………………………………………………………… 9 How a Solar Panel Water Heating System Works ………………………………………………… 10 Benefits of Installing Solar Panels ……………………………………………………………………… 10 Cost Savings of Installing a Solar Thermal System ……………………………………………….. 11
The Essay on Renewable Energy and Solar Windows
... anything on his utility bill (Lasko1). Solar energy systems are another renewable energy investment that can help cut costs ... heating energy obtained from 180 kwh of electric resistance heating ($7-$12 at most electric rates). Besides solar windows, solar chimneys are the most common solar heating systems ... we’re going to add solar panels with it to increase our output of energy. ” By combining both ...
3.2.1 3.2.2 3.2.3 3.2.4 4 5
Conclusion ……………………………………………………………………………………………………………………. 12 References …………………………………………………………………………………………………………………… 13
Table of Figures
Figure 1 Geothermal Heat Pump configurations ………………………………………………………………………… 6 Figure 2 Schematic Diagram Showing How a Heat Pump Works (HPI 2010) ………………………………….. 7 Figure 3 Schematic of a Flat Plat Solar Panel ……………………………………………………………………………… 9 Figure 4 Schematic of an Evacuated Solar Tube Collector (GreenTerraFirma 2010) ……………………… 10
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1 Introduction
The aim of this assignment is to investigate whether the energy profile of an existing residential house can be improved by using renewable energy systems. With increasing awareness of the serious environmental problems due to fossil fuel consumption, efforts are being made by homeowners to install energy-efficient and environmentally friendly systems by utilisation of nonpolluting renewable energy sources. In 2008 the “average” dwelling consumed a total of 24,444 kWh of energy based on climate corrected data. This was comprised of 18,882 kWh (77%) in the form of direct fossil fuels and the remainder (5,557 kWh) as electricity (Howley, O Gallachoir et al. 2009) with space heating and domestic hot water accounting for over 70% of household energy consumption (SEAI 2010).
The Essay on Renewable Energy Source Solar Water Passive
... safe drinking water. Solar pumps are helping to solve this problem by supplying clean water from wells and boreholes. The use of nonrenewable energy has ... RENEWABLE ENERGY SOURCE SOLAR POWER Solar energy is a renewable resource that is environmentally friendly. Unlike fossil fuels solar energy is available just about everywhere on earth. And this ...
In this report the existing energy usage in terms of space heating of an “average” Irish domestic dwelling was calculated and various renewable energy systems suitable for improving the space heating efficiency of the house were discussed. Then incorporating the selected renewable energy systems (heat pumps and solar panels) into the house, the energy profile of the dwelling was reexamined to see whether the energy profile of the house had improved. The report also makes reference to the cost of introducing the new system, including the materials and installation costs and considers the payback period of the system.
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2 Renewable Energy Systems
At present there are several opportunities for homeowners to incorporate renewable energy resources in they’re homes. Using renewable energy has many benefits such as; reducing energy costs, the reliance on fossil fuels and the impacts on the environment. Currently in Ireland the most practical renewable energy options relate to space heating and domestic hot water which account for over 70% of household energy consumption (SEAI 2010).
2.1 Renewable Energy Options in Ireland
Section 3 of this report focuses on improving the energy profile of an existing dwelling by installing a heat pump and solar panels. However, in relation to space heating and domestic hot water, all of the following renewable energy options are available in Ireland:
Passive Solar Design
Incorporating passive solar design into an existing home can bring substantial benefits in energy savings and comfort. Passive solar design uses the energy freely available from the sun to provide heating and lighting in buildings along with measures such as insulation and high energy performing windows/doors can reduce energy bills. Also passive ventilation and cooling techniques can help to eliminate the requirement for wasteful artificial ventilation and cooling (SEI website).
Wood Fuel
Using wood fuel instead of peat, coal and gas to heat houses is a sustainable choice and makes a positive contribution to the environment. Wood is ‘CO2 neutral’ the amount of CO2 wood releases during burning is equal to that which is absorbed during growth. In contrast burning fossil fuels releases GHG’s as well as other damaging pollutants. Wood fuel also takes only 5-20 years to grow, whereas peat and coal are formed over thousands of years. Modern highly efficient stoves and boilers make wood fuel a practical and sustainable option for today’s lifestyle.
The Term Paper on Heat Pump
One of the limitations of using refrigerant mixtures to achieve capacity modulation is that the range of capacity control and the temperature glide are both functions of the difference For applications in residential heat pumps, in boiling points of the two pure components. the temperature glide for the mixture should not exceed 30 F (16.7°C) (Radermacher 1986). Operation at. temperature glides ...
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Heat Pumps
A heat pump is an electrical device that extracts heat from the environment (air, ground or water) and operates most efficiently in moderate climates. It typically replaces an oil or gas boiler and operates for c.a 40-50% of the cost of a fossil fuels boiler (HPI 2010).
Heat pumps use a small amount of electricity to upgrade the amount of heat gathered from the environment to a usable level indoors and are an excellent source for underfloor heating in particular. Heat pumps can also operate in reverse to cool houses by collecting the heat inside the house and pumping it outside. Installation costs are similar to those of a conventional heating system but running costs are much lower (SEAI 2010).
Solar Panels
Active solar heating systems can offer economical hot water and space heating. In Ireland, solar panels can provide around 60% of the annual hot water requirements for homes and buildings (SEAI 2010).
A solar water heater produces hot water by transforming solar energy into heat through its solar panels. The heat is stored in a large hot water cylinder so that it is available when required. It converts both direct and indirect sunlight into heat so it operates even when the sky is overcast.
2.2 Renewable Energy Grants
Sustainable Energy Ireland is the Irish government body regarding grants for renewable energy solutions which they operate under the “Greener Homes” Scheme and the following grants are available under the scheme in relation to both solar panels and heat pumps (SEAI 2010) as an incentive to homeowners to install renewable energy systems: Solar Thermal Space and or Hot water heating (Evacuated Tube) €300 per m2 (to max.6m2) Solar Thermal Space and or Hot water heating (Flat Plate) €250 per m2 (to max.6m2) Heat Pump – Horizontal ground collector €2,500 Heat Pump – Vertical ground collector €3,500 Heat Pump – Water (well) to water €2,500 Heat Pump – Air source €2,000
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3 Improving the Energy Profile of a Domestic Dwelling using Renewable Energy Systems
The Review on Solar Water Purifier
... reducing the effects of hard water. In water systems subject to heating hardness salts can be deposited ... BACKGROUND INFORMATION Solar water purifier is a device that purifies water through solar energy. Dirty water is a ... which can’t penetrate through the glass thus heat is retained. 2. Energy is readily ... and containment – The majority of water must be pumped from its source or directed into ...
This section of the report focuses on the improvements that heat pumps and solar thermal systems can have on the energy profile of a domestic dwelling, as these technologies are considered to be two of the most viable renewable energy system installations in Irish residential households.
3.1 Scenario 1: Installing a Heat Pump in a Domestic Dwelling
A heat pump can take low temperature heat and upgrade it to a higher, more useful temperature which can result in savings in fossil fuel consumption and thus a reduction in the emission of GHGs.
3.1.1
Types of Heat Pumps
The two main options as heat pumps in Ireland are; air source heat pumps and geothermal heat pumps. 1. Air-to-water heat pumps use the heat in the ambient air to provide efficient heating and hot water. Because the air is abundantly available, air source heat pumps have the advantage of low installation costs and minimal space requirements, while relatively mild winter temperatures in Ireland mean excellent levels of efficiency and performance can be achieved throughout the year (Pure Energy Technology 2010).
2. Ground source heat pumps (GSHPs), often referred to as Geothermal Heat Pumps (GHPs) draw heat into a home from the ground, which maintains a nearly constant temperature of 10 – 16 oC (Krigger 2001) below the frost line. The main benefit of using GSHPs is that the ground temperature is higher than the mean air temperature and is not subject to the large variations experienced by air. They are also a well established technology with over 550,000 units installed worldwide (BRESEC 2004).
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Figure 1 Geothermal Heat Pump configurationsi
Some of the most important aspects of choosing a heat pump installation are accurate calculation of the buildings heat loss, its related energy consumption profile and the domestic hot water requirements, as this will allow accurate sizing of the heat pump system.
3.1.2 i)
The Essay on Solar Cell Energy Proteins Photosynthetic
Summary: Researchers have developed a solar cell that converts sunlight into energy through the photosynthetic's of plants. Grounded and purified spinach to harvest photosynthetic proteins. They did this because this released a necessary protein. Proteins act as cell membranes, allowing the functioning of proteins outside their natural environment. Proteins absorb light and deflect electrons in ...
How Heat Pumps Work Brine circulates in a collector coil and absorbs the heat from the bedrock, ground, air or water.
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At the heat exchanger (evaporator) the tepid brine in the collector coil meets the ice cold refrigerant in the heat pump, which is then heated a few degrees and evaporates.
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Then, the compressor compresses the refrigerant. The heat that is then generated is transferred via a heat exchanger (condenser) to the house’s heating system.
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The refrigerant circulates and an expansion valve lowers the pressure and the refrigerant becomes cold again. The process begins again when the refrigerant meets the tepid brine from the collector coil.
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Figure 2 Schematic Diagram Showing How a Heat Pump Worksii (HPI 2010)
3.1.3
Benefits of Heat Pumps
As well as reducing purchased energy consumption and resulting in low CO2 emissions, heat pumps have a number of other environmental and operational advantages: High reliability (few moving parts, minimal exposure to weather) High security (no visible external components to be damaged) Long life expectancy (typically 20 – 25 years) Low noise and maintenance costs No flue or ventilation requirements No local pollution
3.1.4
Cost Savings of a Heat Pump versus an Oil Burner
In 2010 a project carried out by Ashgrove Renewablesiii, an Irish company specialising in heat pumps and solar panels, homeowners interested in comparing the renewable solutions for space heating against a traditional fossil fuel system and differentiating their options in terms of installation costs, and running costs requested a cost analysis of both systems. The cost estimates for installing and running both systems are outlined below: (Buckley 2010)
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Examining a heating system installed for a domestic customer in a 2,500 sq. ft., detached four bedroom dormer home new build to current building regulations. An oil boiler central heating system providing heat to a traditional radiator system was quoted at €3,780 to install. The annual running cost associated with oil fills and one boiler service was calculated at €1,890. Option A: Install a Geothermal Heat Pump which would provide heating and hot water to the home for an installed cost of €11,200 (including ground collector pipework).
The annual running cost would be €650 of electrical energy, plus one service at €130. In order to achieve the highest possible savings the use of underfloor heating is recommended when installing a heat pump. Underfloor heating will ensure the most efficient operation of the system and provides a more comfortable and controllable means of heating the home. The installed cost for this home was calculated at €4,550. Option B: An alternative solution was suggested in the form of an Air to Water (A2W) Heat Pump. This unit draws outside air through itself and in a similar fashion to the geothermal unit it provides hot water inside the home. An A2W unit means less installation work as there is no ground collector installed. This solution would cost €11,450 to install, with annual running costs of €890. The simple payback period for the current project is estimated to be approximately 5 years. Over a 30 year period the oil boiler would cost €56,700 to run (without taking increases in oil prices into account and assuming the boiler does not need to be replaced) while the geothermal heat pump would cost €9,500, a saving of €32,650 (including the initial cost of the underfloor heating).
An air to water heat pump would provide savings of €29,700 over the oil boiler system.
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3.2 Scenario 2: Installing a Solar Thermal System
Solar heating works by capturing the sun’s heat through solar panels through either flat panels or evacuated tubes and uses this free energy to heat the water.
3.2.1
Types of Solar Panel Heating System
There are two main options for solar panel heating systems in Ireland are: 1. Solar Flat Panels look like a flat panel of glass similar to windows that you see on roofs of houses. It is a flat plate absorber fixed in a frame between a single or double layer of glass with an insulation panel at the back. These are fixed through the roof onto the rafters and all pipe work is sealed and runs back into the hot water cylinder tank (Eirgreen 2010).
Figure 3 Schematic of a Flat Plat Solar Paneliv
2. Solar Evacuated Tubes are a series of tube panels side by side made of two layers of glass. This allows the sun’s heat to be absorbed through the tubes of sealed glass efficiently but will not allow the heat to escape. The system works similar to a thermos flask in the way that no heat is allowed to escape due to the vacuum (Eirgreen 2010).
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Figure 4 Schematic of an Evacuated Solar Tube Collectorv (GreenTerraFirma 2010)
3.2.2
How a Solar Panel Water Heating System Works
The components of a solar panel water heating system include(Eirgreen 2010): Solar Panel Collectors – to capture the solar energy; flat plate or evacuated tubes Circulation System – to move fluid between the collectors and the hot water system Control System – for regulation and to prevent overheating Hot Water Cylinder Tank – with fitted insulation for storing water and keeping it hot for longer.
3.2.3
Benefits of Installing Solar Panels
Some of the benefits of installing solar panels are:
Reduce your heating costs. Use less oil, gas or electric for heating your house Increase the value of your property and improve a Building Energy Rating (BER) Free hot water Reduce your CO2 emissions and your carbon footprint Free energy from the sun Environmentally friendly 10
3.2.4
Cost Savings of Installing a Solar Thermal System
In another project carried out by Ecologics, an Irish company who install solar panels, homeowners interested in installing a renewable energy system for improving the efficiency of their domestic water heating, requested a cost analysis of installing and operating the system. The cost estimates for installing and operating two types of solar panel systems are outlined below: In this case a solar water heating system installed for a domestic customer in a 1,800 sq. ft., detached four bedroom home new build to current building regulations is examined. The average person uses between 45 and 60 litres of hot water per day, therefore on average a 300 litre tank with 2-3 solar panels would be sufficient for up to 5 people. Also the solar panels require 1-2 days to install, with little or no interruption to daily life and operate at no cost to the homeowner once installed; the energy from the sun is free. Option A: Install a Flat Plate system consisting of 3 panels mounted on the roof of the property and a hot water cylinder tank of 300 litres. The panels are bracket mounted and therefore are suitable for installation on a pre-existing roof as the removal or replacement of tiles is not required. A total installed cost of €6,000 is estimated for the solar water heating system. Option B: An alternative solution would be to install an Evacuated Tube system, which is mounted on the roof of the property. It is also bracket mounted and therefore does not materially alter the roof. The panel is relatively small, 20 tube panel measuring 2 sq. m. The system utilises the light and heat from the sun, converting it into hot water in the system, which is then transferred to the hot water cylinder, reducing the need for hot water to be heated by the central heating system. A total installation cost of €4600vi is quoted. In the year following the installation of the system it is estimated that the homeowner’s electricity bill will be reduced by an overall 16%. The solar panels have the capacity to produce the equivalent of approx. 220 kWh of heat per month therefore the homeowner estimates that their oil fired central heating costs will be reduced by at least 20% per annum. Both solar water heating systems over their life span (approx. 25 years) work quite efficiently and provide solar heating regardless of the climate and they are also covered by a guaranteevii. However, a solar evacuated tube collector is approx 25% more efficient in cloudier conditions (Eirgreen 2010).
Although from time to time the tubes may blow and to maintain their efficiency, the tube will have to be replaced, whereas solar flat panels are sealed and require no maintenance at all. The payback period for solar hot water systems is estimated to relatively short, with average paybacks of 5 – 6 years common in Ireland. (Ecologics 2010) 11
4 Conclusion
Apart from the financial benefits of choosing a renewable technology, householders can enjoy high levels of comfort through enhanced controllability and a cleaner source of heat, which is friendlier to the environment than conventional fossil fuel systems. Although the cost savings calculated in Section 3 of this report use figures from companies promoting these technologies and are therefore best case scenarios, they illustrate that installing renewable energy systems in domestic dwellings can dramatically improve the energy profile of the building. Factors related to the energy savings available with a renewable energy unit include the size of the house, its heat loss and level of insulation, as well as the sizing of the unit, it’s efficiency, local climate and energy costs, the lifestyle habits of the occupants, the efficiency of alternative heating systems, interior temperature settings and the heating options selected (Mustafa Omer 2008).
Furthermore, in order to maximise the amount of energy savings it is recommend that insulation and heating system controls are also installed.
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5 References
BRESEC (2004).
Domestic Ground Source Heat Pumps: Design and installation of closed loop systems. Energy Efficiency Best Practice in Housing, BRE’s Sustainable Energy Centre. Buckley, P. (2010).
“Case Study: A typical domestic installation makes savings over it’s lifetime.” Retrieved 09/11/2010, 2010, from http://ashgrove.ie/blog/category/projects/. Ecologics (2010).
“Solar Solutions.” Retrieved 10/11/2010, from www.ecologics.ie. Eirgreen (2010).
“Solar Panels.” . Retrieved 9/11/2010, 2010, from
GreenTerraFirma (2010).
“Evacuated Solar http://greenterrafirma.com/evacuated_tube_collector.html.
Tube
Collector.”
from
Howley, M., D. B. O Gallachoir, et al. (2009).
Energy in Ireland 1990 – 2008. Energy Policy Statistical Support Unit, Sustainable Energy Ireland. HPI (2010).
“Heat Pump Information.” Retrieved 09/11/2010, 2010. Krigger, J. (2001).
Air Source Heat Pumps, National Renewable Energy Lab., Golden, CO (US).
Mustafa Omer, A. (2008).
“Ground-source heat pumps systems and applications.” Renewable and Sustainable Energy Reviews 12(2): 344-371. Pure Energy Technology (2010).
http://www.pet.ie/heat-pumps.html. “Heat Pumps.” Retrieved 09/11/2010, 2010, from
SEAI (2010).
“Renewable Energy for the Homeowner.” Retrieved 09/11/2010, 2010, from http://www.seai.ie/Renewables/Renewable_Energy_for_the_Homeowner/.
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Reproduced from HPI (2010).
“Heat Pump Information.” Retrieved 09/11/2010, www.heatpumpsireland.com Reproduced from HPI (2010).
“Heat Pump Information.” Retrieved 09/11/2010, www.heatpumpsireland.com iii Buckley, P. (2010) cited in “Case Study: A typical domestic installation makes savings over its lifetime.” Published by Ashgrove Renewables. Retrieved 09/11/2010, from http://ashgrove.ie/blog/category/projects/. iv Reproduced from Ecologics (2010).
“Solar Solutions.” Retrieved 10/11/2010, from www.ecologics.ie. v GreenTerraFirma (2010).
“Evacuated Solar Tube Collector.” from http://greenterrafirma.com/evacuated_tube_collector.html. vi Based on 2006 figures published by the Energy Savings Trust (2010).
Accessed on 9/11/2010. From http://www.energysavingstrust.org.uk All figures were converted from pounds sterling to euro based on the 2006 exchange rate of 1.467 from www.xe.com vii Ecologics (2010).
“Solar Solutions.” State that their solar panels are covered by a 10 year guarantee however, this may vary with other suppliers. Retrieved 10/11/2010, from www.ecologics.ie
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