Energy demand reforms
The world’s energy requirement has seen extraordinary change in the last century. The fossil fuels like coal and petroleum have become the main source behind the speedy world growth. Its not only the factories and motor vehicles which are the main reason behind the heavy consumption of these fuels but also the power stations like the thermal power stations which requires very large quantity of these carbon based fuels to produce electricity for the consumption of common public. Between the period 1999 and 2020, World energy consumption is projected to rise by 59 percent reaching 607 quadrillion British thermal units (BTUS). But the point of concern is not this increase in demand. It’s the world’s dependence on fossil fuel which is the point of concern. The world gets most of its energy from nonrenewable energy sources, which include the fossil fuels–oil, natural gas, and coal.
Another non renewable energy source is the element uranium, whose atoms are split through nuclear fission to create heat and ultimately electricity. These non renewable energy sources actually cause great environmental problems. The Green House effect has caused major change in the world’s climatic pattern. The Kyoto Protocol agreement made under the United Nations Framework Convention on Climate Change (UNFCCC), countries that ratify this protocol should commit to reduce their emissions of carbon dioxide and five other greenhouse gases.
There have been many other attempts not only at the level of UN but also at national as well as district and town level to make people aware of these harmful gases as well as different power saving techniques. There is a need of tackling the above mentioned problems at micro level involving each and every town and locality. According to 40% House Project by University of Oxford, energy consumption in residential areas in UK can be reduced by 60%. The paper has focused primarily on demand-side influences on carbon emissions in residential areas with an explanation to make a comprehensive change in the same through government policy. Understanding the energy need of every household and extending the same to the whole town can help the policy makers in tackling energy related problems like consumption and carbon emission.
2. A Small Town “Enerzia” and its Energy Consumption
In order to analyze the energy consumption and requirement of a small market town, a detailed model of the town with approximation of population and the number of households and its average size has to be developed. The modeling process required for this should contain information on the population size, energy needed in form of oil, gas and electricity and its pert capita consumption and the approximation according to some standard. The over all energy requirement of a place depends upon both environmental condition and the standard of living. The report contains the standard cases set according to the standards of European Union.
Beginning with a small town located in either of the twenty five member nations of European Union, the assumption making phase starts with the population size. The hypothetical town is called Enerzia with a population of around 10,000 people and climate being cold temperate with sub-zero temperature in the major part of the year. Based on reports of European Union, per capita GIC or Gross Inland Consumption is 3773 kgoe/cap (Per Capita Kilogram oil equivalent). It is the quantity of energy necessary for the inland consumption of the geographical entity under consideration. The GIC of this place will approximately be equal to 37730 toe (Ton Oil Equivalent). Now in the report, it has been assumed that the main sources of energy in Enerzia are oil; gas and solid fuel comprising mainly of coal. This also includes the above mentioned materials being used for power production. The main raw material for power production has been oil followed by gas and coal. The oil mainly used by the residents is basically of three types.
They are petrol, diesel and heating oil. The use of heating oil is for thermal heating. As in the above portion it has already been mentioned that the climatic condition is mainly cold temperate, so the most of the households in Enerzia uses heating oil as a fuel to burning furnaces or boilers to keep the house warm during winter or cold environment. Petrol and diesel are also used for transportation purpose. There is no use of coal as a household fuel but the town receives energy in form of electricity from a thermal plant located at some other place but the grid provides the electricity generated from that power plant to this place. So, the major source of energy in Enerzia is the fossil fuels with oil forming the major block comprising 55 % of total energy consumption. Natural gas is used in households.
In many homes the food is cooked and clothes are dried by gas apart from heating house and water. Electricity production is also done by the same. Hence natural gas comprises about 35 % of the total energy consumption in Enerzia. The rest of the energy requirement is met through coal and is consumed in directly by the people of Enerzia through the power consumed by them and is produced at the power station utilizing coal for producing the same.
Coal & others
3. Enerzia’s energy solution
The use of fossil fuel for the purpose of satisfying the energy needs of the society and moving the wheel of development has caused great stress on resources and climatic condition of the world. Change in climatic condition is visible trough the rising trend in the global average temperature. The average temperature has risen by about 0.6°C globally while Europe has seen the rise of the mean temperature by 0.9°C. The concentration of Greenhouse gas including the CO2 is highest if the data of the last hundreds of thousands are taken into consideration and compared with that of last few years. It’s been the excessive use of energy resources for human activity has been the cause behind the emission of these gases. The urgent need is to slow down this climatic change and finally an end to all those processes that are behind this effect.
For the betterment of society and environment, the most important thing is to make changes in energy usage pattern right from the ground level i.e., the households. Energy usage awareness at residential places will make more impact in people’s psyche and understanding. Beginning with the motive mentioned above, first of all the processes which are normally used for power production has to be taken into account. Since places in Europe including Enerzia is a very large consumer of electricity. The processes involved in production of electricity as mentioned earlier requires oil, natural gas and coal. These processes can be replaced partially or if possible totally by those techniques which involves renewable energy sources like wind or solar energy with zero percent emission of greenhouse gases.
Producing electricity through wind is a quite old but its commercial usage is relatively young. The world has seen an annual growth of almost 30% in power production through wind energy. The current annual global power production through wind energy is now 58, 982 MW with more than 69% of it being produced in Europe. In most of the European nations, it forms the major portion of annual requirements. Power production through wind energy now forms 20% in Denmark and about 5% in both Germany and Spain of the total power production. But the actual winner is none other than Netherlands. Netherlands is the pioneer in aero wind power generation. Its 76% of electricity is actually met through power generation from wind energy. The electricity from a wind machine can be distributed through various ways depending on the size of the turbines used. In case of large turbines, the connectivity with the national grid becomes a necessity and the power generated can be commercially sold. But smaller areas can have their own micro-grids. In that case, hybrid systems comprising of a number of sources should be preferred. The main reason behind all this is to use other sources in case of low wind speed. Electricity storage can be used when the power produced though wind exceeds the required amount. Power storage options are of great use in rural areas where requirement is much less when compared with town or cities. Power stored in batteries can be used when requirement is at a remote place. These batteries can be returned to the charging stations so that it can again be recharged. Smaller turbines are also available for private ownership and are of the range 50 – 150 watt.
3.1 Power generation through Aero Wind Generator
The condition in Enerzia is very much suitable for power generation through aero wind generators. The annual mean wind speed of around 6.5 m/s is quite suitable for uninterrupted power supply. The aero wind power model being successful in almost whole of Europe will greatly reduce environmental stress due to the use of fossil fuel. The model of installation of wind turbines implemented in most of Municipalities of Netherlands can easily be applied in Enerzia. Apart from promoting individuals to install privately owned small wind turbines of 80 kW each to bigger ones with capacity ranging from 300 kW to 1500 kW being owned by government authorities or any power production company. The most important factor in installing a wind farm is the wind speed. According to basic science concepts, the power in the wind increases by a factor of 8 with doubling of its speed. So, even a minor change in wind speed can cause large change in the production of power. Apart from tackling environmental concerns, it’s the cost of maintenance which is also a very attractive proportion behind the success of wind turbines. A modern aero wind generator can be operated for more than 20 years or 120,000 with very low cost of maintenance. In contrast, a fossil fuel based engine has a design lifetime of 4,000 to 6,000 hours.
The involvement of local community in overall process of power production will make the whole process of installation and power production through wind turbines better and create more energy awareness among local citizens. They can be involved in the process of installing the anemometer as well as the wind turbines. The installation of wind turbines is preceded by site selection. The ideal and appropriate sites are mostly located near the periphery of the town. The site selection is mostly done according to the reasonable wind speeds, grid connectivity and ease in the installation of turbines. Since the site selection is very much dependent on wind speed, the data log is maintained from the output obtained from different anemometers. Local members of the town should be trained in operation of data logger after the installation of the anemometer. Training of locals is the key aspect of the whole project right from the site selection to power production. After the selection of sites, the potential of turbine accommodation is looked into.
The turbines are installed in clusters while taking the direction of wind as the main deciding factor. Different clusters have different orientation because direction of flow of wind actually varies periodically over a long period of time in year as well as variation during the day time. The landscape considerations are taken into account while making decision on the size of clusters and the type of turbines. Maximum capacity is normally obtained smaller turbines but installation of the same requires a very large number of turbines with very significant land escapes.
Similarly larger turbines are basically meant for large plain lands and have different sort of benefits. So, the turbines are erected in lines, clusters or double clusters depending on feasibility and ground realities. Normally a combination strategy is preferred according to which a mixture of turbine sizes while considering the maximum possible output of power.
Wind Turbine clusters with turbines having different orientation
In case of electricity produced is higher than local demand, the national grid network can easily utilize the extra electricity produced in transferring the same to other towns. This means the main objective of reduction in CO2 emission can be achieved with contributions from other regions.
3.2 Power Generation through individually owned aero wind generator
A normal household should also be encouraged to own wind turbine so that their dependence on local supply can be reduced. Technically a home should be served simultaneously by the wind turbine and a local supply system. The turbines used in residential areas have higher cut-in speed ranging between 7 to 10 mph. The turbine will not give any output in case of speed being less than the cut-in speed and the house hold will depend on the local supply. As wind speed increase, turbine output increases and the household dependence on local supply decreases accordingly. A wind turbine is normally provided with 80- to 120- feet tower. This much height is very necessary to raise the wind turbine so that it can function without any turbulence which might get occurred due to trees.
Wind Turbine installed in a household.
Wind velocity at higher altitude is more than that near ground level. The higher speed of wind finally enhances the performance of the wind turbine.
3.3. Power Generation through Solar photo Voltaic Cells
Photovoltaic cells are a very reliable source of energy if we consider environmental issues. The electricity produced through this technology is quite clean and lefts no by product. A complete photovoltaic system is composed of photovoltaic cells, devices which convert light energy directly into electricity. The source of light is none other than sun and hence is also called as solar cells. The solar photovoltaic cells can be of great use in remote off grid applications. It can be used for individual usage through installation of relatively larger solar plates over the roof or sides of a house. A typical solar power production device consists of one panel of capacity ranging between 50 – 60 W, a controller unit and batteries. It can be utilized in providing power for lighting, radio and television. Solar panels can make electricity in all kinds of conditions. It can a cloudy sky or full daylight in all seasons of the year. But the same doesn’t work during night. So to get over this problem, the energy generated during daytime must be stored for later use. Rechargeable batteries are of great use and are often charged with solar arrays. With advancement in technology, modern photovoltaic systems are usually equipped with some electronic charge controller. The charge controller maintains the efficiency of battery feeding process. It prevents the solar panel from over charging the battery and at the same time protects the panels from any electric damage.
Photovoltaic cells are most of the time arranged on a panel to form a solar module. Then solar arrays are formed by linking the modules in series. In residential installations, cells are installed either parallel to the roof plane or tilted up so that optimum power production can be achieved. PV Panels arranged in a fixed position and are of very lightweight. But this arrangement is usually less than the optimal production because their orientation to the sun is usually at an angle. There fore, energy collected per unit area of array is lesser than the possible optimum generation. Tracking array are better in utilizing the panel to its max but are available at much higher cost.
Panels installed on the roof of a house.
3.4. Biomass and its usage as a source of energy
Europe has always been a front runner in looking into better and better ways for satisfying its energy needs. Apart from what that have been mentioned earlier, European Union is now looking into those resources which doesn’t require another million of years to redevelop and should also be termed as a clean fuel. Use of biomass is a very good way to satisfy the energy needs of Europe. It is basically agricultural and forest residue. Fuels derived from these materials contain less sulphur and hence can help a lot in reducing atmospheric pollutants and thereby improving the air quality. Since, the complete process of energy production from biomass will finally result planting of energy crops, so this will give a major boost to rural economy and also help in maintaining agriculture; forest and green cover. The need of the hour is to understand the present position and identification in the areas which requires technological breakthrough. Since the energy crops and biological residues are the major ingredient, realizing energy through this process will require involvement of almost whole of rural region and work has to be done with greater involvement of people from the smaller regions including those from semi urban places like Enerzia can contribute a lot in this case.
3.4.1. Biomass and Electricity generation
Steam Turbine based power stations can be developed and operated through the burning of solid biomass or wastes. Improving performance of the system will require variation in design. The energy efficiency can be achieved through the condensation of exhaust steam and increase in the number of stages of energy usage. The efficiency enhancement of the biomass power plant will significant use of the heat produced from the process. The steam extracted from the turbine will help in heating water thereby making the complete system not just a power plant but a combined heat and power plant. Heat may also be converted and stored in smaller system in form of water and again be used for other processes.
Turbine for producing power through biomass.
By-products from industrial processes as well as common households can very efficiently be used in other sectors including power generation as well as generation of steam. These techniques not only save money but also contribute a lot in the reduction of land and water pollution. Biological waste can be reassessed and can be converted into biomass and efficient power usage. Other household and commercial usage of these as fuel can be seen when people buy wood and wastes including garden trimming for water heating and space heating.
Developing a biogas plant with the sole purpose of serving the energy need of the local community can also be revolutionary step in localized solution to energy requirement of a place. Biogas plant scan be used in generating electricity as well as cooking gas. This technology is very much successful in most of the region of Europe with a large scale implementation in Italy. The small towns can have their own micro-grid with electricity being generated by a number of renewable energy sources including the biogas.
3.4.2. Biomass and bio-fuels for direct consumption
Solid biomass can be turned into liquid clean fuels and can be used in combustion engines. The main benefit of it is the use of these fuels for transportation as well in oil-burners as well as electricity generation. These liquid fuels can be generated through biological conversion to ethanol and chemical conversion of vegetable oils. It will a great boon for those who want replace fossil fuels with the cleaner ones while continuing with the technology presently available in the market.
The bioethanol plant is going to be a revolutionary intermediary between current technology and future one. It not only produces the clean fuels but also animal feed in form of residual fibre from the seeds. Energy crops will be a boon to agriculture sector. In the current market economy agricultural sector has actually lost its importance and the government in many countries has to extend excise help and many other incentives to sustain its growth. But the cultivation of energy crops will give this sector a much needed up thrust. Low cost fibres after being operated with acids and enzymes derived from fungi or bacteria which will finally release sugar from these fibres. The sugar obtained is now available for the generation of bio-fuels. The best part of this process is the generation while using the natural techniques to get what till now was obtained through chemical processes applied on petroleum.
4. Enerzia and household energy efficiency
Household energy consumption has always been very less when compared to industrial consumption. But a very big portion of it is actually getting waste due to the use of poor consumption techniques and lack of insulation in houses. Residential usage of energy is directly proportional to number of households. The annual growth factor increases proportionally with the number of new households. The future and current demand of energy is very much dependent on pr capita energy usage as well as amount of living space. The amount of living space has its implications on space heating and cooling. The quantity of energy for water heating and the number of energy based appliances depend on the size of the household.
4.1 Energy demand: Household size and living space
Per capita energy consumption depends a lot on size of the household. In larger households, per capita energy bill is much less than that with smaller size. Energy waste in smaller household is much higher because of higher per capita space. The space and size of the house are an important deciding factor behind the consumption of energy. The space is also a deciding factor behind the number and size of appliances that will fit in the dwelling. Processes like space heating or cooling as well the operation of appliances forms a bigger part of the total energy consumption.
4.2 Household requirement: thermal comfort and space heating
With every passing year, the overall demand for space heating is increasing. Efficiency has also been improved. But with rising population and number of households the gain through improved efficiency has actually nullified. The requirement of energy needed for per capita consumption remained the same because of the efficiency got compensated for better and more use of this resource. The need of the hour is not just the further improvisation of the resources but also its preservation or better to say energy conservation. Looking into the need of thermal comfort, the human body needs to maintain the internal temperature of around 37°C and a number ways are there to maintain this thermal need. The space and room heating or cooling is a very popular way of providing thermal comfort to human body. This overall involves many direct and indirect interactions between humans, climate behavior, household or building design, its heating and cooling processes and finally insulation technologies. The major factor which actually gets importance is the energy efficiency. The level of energy efficiency is a point of study. The better its standard is the lesser will be the dependence of the household on quantity of energy usage. It will also ensure adequate as well as affordable availability of energy for each and every household of the society. The efficiency ensures improved comfort and finally making improvement in overall performance of the household with more cost, health and environmental benefits as well as for the society. The improvement in residential energy efficiency is actually realized as energy savings. The per capita energy usage is a very important reason for energy efficiency. Number of persons living in a house hold is one of the deciding reasons. If few persons live in bigger houses then per capita energy usage will considerably be very high and result in wastage and lesser efficiency level. Space heating or cooling depends not only of number of persons utilizing the resources but also the size of the houses. So bigger the size, more energy will be needed for maintaining thermal equilibrium.
The improvement in efficiency level of Enerzia will require proper mixing of number of people in a house hold with the size of the houses. The number of people should decide the size of the house being allotted by the authorities. Joint family concepts should be promoted and well rewarded with free energy coupons as well as social benefits like life insurance as well as general insurances. The energy awareness programs with sole motive of teaching common people of ways to make personal contributions to the country, society and environment with simple steps like energy usage reduction as well as improving energy efficiency should be undertaken.
4.3 Space heating and cooling: a major energy consuming process
If we look the energy requirement pattern of a normal household, we will find that heating and cooling systems are the largest single consumers of energy in buildings or houses. The sole purpose of these systems is to condition the air within a building and proving thermal comfort to its occupants. The complete system for heating and cooling purposes consist mainly of chillers, boilers, cooling towers, and pumps. There can be a central heating and cooling systems as well as unitary systems that combine heating and cooling. With improved technology and smart energy use, both the systems can be improved to a very considerable level so that the overall purpose of saving energy with better energy or thermal comfort to humans can be achieved. Statistical information suggests that a normal house hold in Western Europe normally consumes around 55 % of the total energy consumption for space heating. So any major effort that will be needed to enhance energy efficiency will require tackling of issues related to improvement in space heating process. It should then be followed by insulation improvements as well energy efficient building structures.
The strategy required for the optimization of resources involved in the heating and cooling system begins with load analysis. Each and every household in Enerzia should measure its heating and cooling loads. The system providing thermal comfort in form of heating and cooling should be sized properly. Different components involved in the heating and cooling system should undergo an upgraded. Old boilers ought to be replaced by new condensing ones. The chillers of the cooling system have to be replaced with new and more energy-efficient non-chlorofluorocarbon based models. Installing variable-speed drives or VSDs on the pumps and cooling tower fans.
These changes have considerable energy efficiency. In case of applied technology being central chilling, energy saved will be around 15-35 % while in case of unitary A/C the energy saved is of around 20-35 %. Similarly the boiler based heating system will give a result in form of energy savings of around 10-30 % while the furnace based system will yield a result of 5-25 % efficiency.
Delving into the form of energy normally needed for these two types of occupant comforting systems, one can easily see that the cooling processes needs almost a third of the electricity consumed in a typical building while the heating systems is basically use natural gas or oil as the primary fuel but at the same time one can see that there are houses which uses electricity for the same. The systems are for the sole purpose of conditioning the air within a building.
These main system components are chillers, boilers, cooling towers, and pumps. The cooling systems needed in a normal residential household generally have to be of higher space conditioning capacities than heating systems, because a sizable portion of the total heat requirement is supplied by waste heat from people, lighting, and appliances. The same waste heat is a bane for a cooling system and hence negates the effect of the cooling system. So, the proper design and operation of these systems can be translated further into significant savings in both the systems.
4.3. 1 Efficiency improvement in processes for Space heating
Improvement in space heating has to begin with replacement processes. Replacing old boilers by new condensing boilers can reduce the energy consumption by at least 5 %. The improved technology undertakes a range of measures which covers the burner, the boiler, automatic control systems and efficient insulation of both boiler and piping pumps with improvement in the hydraulic systems and the radiator systems. The boilers occupy a very major portion of the heating system of a building or house hold structure. Since more than 90 % houses rely on fossil fuel based boilers, they are mainly gas fired or oil fired. The combustion efficiency of these boilers is generally between 65 percent and 75 percent. Insufficient ones may fall below 60 percent in case of efficiency and perform between 40 percent and 60 percent. Modifications and new technology can make these boilers more energy efficient with efficiencies between 85 and 95 percent. So to reduce boiler system energy consumption by 10 to 30 percent by making improvement through replacing the old one with a new, right sized and more energy-efficient boiler system or retrofitting the older one so that it can perform more efficiently.
Replacing an old or inefficient boiler with the most efficient boiler system gives best possible energy savings. These boilers have increased heating surface areas with improved control for fuel and airflow over the varying range of load conditions. The replacement process normally begins with the determination of building’s heating load and according rightsizing of boiler. The rightsizing of boiler is done with an energy-efficient model. The staged system of smaller, energy-efficient boilers operating in combination should be preferred. This technology ensures optimum use of fuel and energy usage as compared to single-boiler system. The older and newer systems can be compared through rated energy consumption at various loads for the old and new boiler systems.
The second way to get over boiler inefficiency is through retrofitting. Existing boilers can give dramatic results after a retrofitting phase. The over all performance comprising mainly of peak- and part-load efficiency, get improved. The main boiler retrofits are the new burners, temperature/pressure reset, boiler economizer and finally baffle inserts. New burners are very efficient and improve fuel combustion and reduce emissions of toxics like nitrogen oxide.
Temperature reset as well as pressure reset controls minimize fuel wastes and hence provides significant energy savings. The pressure reset control matches the supply of steam with the demand of heat required in a space. It saves energy from getting wasted due to decrease in practices of supplying steam at pressure which is more than needed. Similarly system water is reset according to outdoor temperature. If the outdoor increases, the system water temperature is lowered correspondingly. A boiler economizer is used to capture waste heat in exhaust gases and the same is used to preheat the water being feed to the boiler. A natural gas fueled boiler needs to maintain the stack temperature at a temperature of minimum 250° F to avoid the condensation of the water vapor in the gases. The last one being the baffle inserts which induce combustion gases to flow in turbulent spiral pattern thereby increasing the efficiency of heat transfer.
Furnace based heating units are also used for providing thermal comfort for the building and places of residence. The source of heat can be fuel oil, natural gas, electricity, coal, or wood. The main components of a furnace are the heat exchanger, fuel burner, blower or fan, controls, and housing. Replacement or the retrofitting can make the furnace energy-efficient. The existing furnaces should be replaced by new, right sized and energy-efficient furnace and in case of retrofitting; the furnace should be provided with additional controls so that it can perform more efficiently. Furnace rightsizing is the very first step for efficient furnace performance. Any high efficiency furnace with condensing heat exchangers will have a steady- state efficiency of almost 94 percent. The heating load is measured and the existing furnace is evaluated in terms of efficiency and capacity. Retrofitting is equally beneficial and can make significant reduction in energy usage in heating process.
This process begins with the installation of new burners because efficient burners improve fuel consumption and reduce the emission of toxics like nitrogen oxide. The two stage setback controls comprising of thermostat with staged supplement heat and a programmable demand limiter can be installed to prevent demand peaks in the morning. The electrically heated space normally requires larger amount of electricity in case of bringing the state from cooler to normal and this two stage setback control helps in maintaining the amount of electricity needed. Another alternative to oil heating can be the resistance heating. This type of heating not only reduces the cost of heating but also makes a very environment friendly impact.
Space heating can also be done through air-source heat pumps. This type of heating is very well suited for relatively warm whether condition. An air-source heat pump system is basically rooftop units either as a complete unit or a split system. The same unit can also be used during cooling mode. While working as a hat pump, it extracts heat from the outside air and provides it to the required space. These heat pumps require supplemental heating source when the temperature drops to a very low level. Split- package heat pumps have got a different design but works on similar concept. Its one part comprises of an air-handling unit located inside the conditioned space and the condenser and compressor are packaged in other unit installed outdoor on a roof.
4.3.2 Efficiency improvement in processes for Space cooling
A cooling system consists of a number of components. For the highest possible efficiency and proper occupant comfort, all the components of the system must work together. Any improvement in the complete set will require individual improvements to be incorporated to each of the equipments. But the changes must be made while considering the system as an integrated unit. This can be understood with the logic that any modification in the design or operation of one set of the components will make an effect on the operation of other equipment within the system. There are basically four types of mechanical compression chillers namely centrifugal, screw, scroll, and reciprocating. Different applications require different types of chiller type. The new chillers are very energy efficient and the amount of energy required by them are almost half of what actually consumed by older ones. Since the World Health Organization and many environmental agencies have called for non-CFC refrigerants, the new chillers are not as efficient as their CFC counterparts; this loss can be offset through a comprehensive upgrades.
Chiller rightsizing depends on the upgrades implementation in the previous stages. It has been found that chillers are often oversized which makes a very significant impact on cost of operation and maintenance. Chillers are often sized according to peak load but it is equally true that it operates most of the time at part loads. So any chiller up gradation should also consider the ratio of time of peak hour to non peak hours.
Free cooling or water side economizer system can be applied under suitable condition, and the same can generate significant energy savings. In cooler, drier climates, this technology can provide more than 75 % of the cooling requirements of an household but in case of warmer climates this water side economizer may provide only 20 percent of the total cooling comfort. Facilities that often require cooling round the year from high sensible heat gains would be most benefited thing from direct free cooling. The whole application would require a large computer room or data center cooled with a centrally chilled water system. This system ensures that in case of an ideal outdoor condition, the chiller can be shut off and cooling load may be served by the cooling tower without any mechanical refrigeration which requires heavy energy.
Building or structures which require transportation of chilled water or condensed water and uses pumps for the same, an integrated approach can reduce the energy usage for the pumping system by over 50 percent. The pumping system can be made more energy efficient by replacing oversized impellers, pumps, and motors with right sized pumps and energy efficient motors which are basically much smaller in size. Pumps are right sized and there by maximum loads can be lowered. It can save energy up to 70 percent. An oversized impeller in an existing centrifugal pump has to be replaced.
boiler 1. http://www.mge.com/business/saving/madison/art/EA25_1.gif
split 2. http://www.airms.co.uk/images/NAHospitalCU1,2.jpg