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Title of Presentation ENHANCEMENT OF THE COEFFICIENT OF PERFORMANCE IN AIR CONDITIONING SYSTEMS BY UTILIZING FREE COOLING A. Al-Salaymeh 1, M. Al-Salaymeh.

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Presentation on theme: "Title of Presentation ENHANCEMENT OF THE COEFFICIENT OF PERFORMANCE IN AIR CONDITIONING SYSTEMS BY UTILIZING FREE COOLING A. Al-Salaymeh 1, M. Al-Salaymeh."— Presentation transcript:

1 Title of Presentation ENHANCEMENT OF THE COEFFICIENT OF PERFORMANCE IN AIR CONDITIONING SYSTEMS BY UTILIZING FREE COOLING A. Al-Salaymeh 1, M. Al-Salaymeh 2, M. Rabah 3, M. Abdelkader 1 1 Mech. Eng. Dept., University of Jordan, Amman, Jordan 2 Jordan Telecommunication Company, Zarka, Jordan 3 Mech. Eng. Dept., Al-Balqa Applied University, Amman, Jordan 1 2nd International Conference on Thermal Engineering Theory and Applications January 3 - 6, 2006, Al Ain, United Arab Emirates 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

2 Contents of Presentation 2  INTRODUCTION  BASIC DEFINITIONS  ELEMENTS OF REFRIGERATION AND AIR CONDITIONING SYSTEMS  COMPRESSORS  REFRIGERANT AND REFRIGERANT FLOW CONTROL  FREE COOLING  ECONOMIC STUDY OF USING FREE COOLING  CONCLUSIONS 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

3 Introduction 3  All sources of energy may be grouped into two general categories:  Income energy, which is the energy reaching the earth from outer space,  Capital energy, which is the energy that already exists on or within the earth.  The utilization of income energy sources is very attractive because they are nondepletable sources of energy and they are relatively pollution free.  Jordan is relatively poor in conventional resources and is basically a non-oil- producing country, i.e. about 95% of its needs being supplied from abroad as crude oil and refined products.  It is therefore unlikely that any future energy scenario for Jordan will not include a significant proportion of its energy coming from Renewable Energy.  It is clear that the government’s plan requires consideration of the increased energy demands of the country and the undertaking of research and development efforts towards solutions of current problems. 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

4 Energy Policy in Jordan 4  The energy demand in Jordan has doubled during the last 20 years, and is expected to continue at the same rate, or even higher.  All recent energy forecast scenarios have shown that national energy consumption might double between 2015 and  Such a rapid increasing demand is due to the high growth rate of the population and the expansion of economical activities in various fields.  By high oil prices, the government is undertaking new measures to improve the situation in the energy sector by formulating and implementing an adjustment plan.  The demand for primary energy in Jordan is 4.8 million tons of oil equivalents (toe), showing a 3% annual growth  The primary energy consumption that was required for electricity generation in 2000 was equivalent to 1.8 million toe.  The average energy consumption per inhabitant is 970 kg oil equivalent.  It is predicted that electricity generation of Jordan will be around and GWh in 2010 and 2015, respectively. 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

5 5 Existing Knowledge & Aim of the Work  The share of solar energy in the total energy mix in Jordan is estimated to be around 1.7% during the year  The expected share of solar energy in the total energy mix in the year 2007 is estimated to be around 2.1%.  All the above-mentioned attempts to ensure Jordan’s energy supply do not eliminate the need to search for new energy sources in the country.  In order to reduce dependence on the imported oil, Jordan has pursued programs for promoting solar energy involving systematic monitoring and assessment of technological developments combined with the implementation of appropriate technologies, demonstrations and pilot projects.  Free cooling technique in air conditioning system can be utilized to save the energy consumption.  The present work shows the economics study of utilizing free cooling in air conditioning system. 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

6 Elements of Air Conditioning 6 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

7 Phases in the Cooling Circuit 7 Compressor makes up the pressure in the discharge line to the condenser coil. Due to the cooling effect of the air flow across the condenser the refrigerant vapour will condense to liquid form and heat will be released to the condenser air flow. The refrigerant liquid will run into the receiver, which the liquid line to the thermostatic valve, always will be full of refrigerant. The filter dryer obtain impurities and humidity. The solenoid valve is operating ON/OFF and is an important part in the “Pump down” system. The thermostatic expansion valve is located just before the evaporator. The valve releases sufficient amount of refrigerant to the give a little superheat of 4-6  C ensuring that all liquid has evaporated. The evaporation of refrigerant takes place at low pressure in the evaporator and because the refrigerant has a low boiling temperature, the evaporation process needs heat energy. Heat is taken from the air passing through the evaporator coil, the result will be that the air flow is cooled. 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

8 Free Cooling (1) 8  Free cooling take place when the external ambient air temperature is less than the indoor air temperature  Air conditioning systems either provide supply air using:  A mixture of outside air and recirculated (return) air from the shiltter room.  100% outside air systems which are generally used in the cases of hospitals, densely occupied areas such as theatres etc.  Free cooling may be used with mixed outside air and recirculation systems by the use of modulating dampers.  Dampers are provided on the outside air intake ductwork, exhaust air ductwork and the recirculation ductwork.  In the event of cool outside air the quantity of outside air is increased and the quantity of recalculated air is reduced to provide the required supply air temperature. In this way cooling by means of refrigeration equipment is avoided altogether at certain times of year and often at night times. 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

9 Free Cooling (1) 9  During cool weather, the outside ambient temperature can help save energy in Air conditioning systems.  The low temperature of the cooling ambient air supply enables free cooling of computer rooms.  Free cooling can be used to save energy whenever the outside wet-bulb temperature drops below the required cooling air set-point.  This energy-efficiency measure can save enough compressor electric power to pay for damper installation costs in less than 2 years.  When the outside air temperature is higher than the room temperature in Summer the dampers will modulate to the minimum outside air position to keep the load on the refrigeration equipment to a minimum.  The free cooling version has a motorized damper that conducts the two flows of internal and external air. When the damper is open it takes the air necessary for cooling directly from the exterior, excluding compressor operation as shown in Figure. 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

10 Principle Operation 10 Free cooling off Free cooling on 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

11 Economic Study of Using Free Cooling 11  The air conditioning system (small shiltter) uses “free” cooling techniques to reduce energy costs.  COP which is the ratio of cooling energy provided divided by the amount of energy used to run the refrigeration plant, has typical values between 3 and 5.  The 4 ton cooling load in JTC buildings represents about kW of cooling load, which is effectively provided with about 3.75 of electrical consumption for a COP of  However there are periods of the year where (in the case of JTC cooling ambient temperature can be utilized to provide nearly free cooling (COP > 90 – where the only energy consumption is from the use of evaporative fans.  The compressor of A/C is shut off during this period, thereby saving energy  The compressor of A/C can be shut down form 1 to as may as 4 months a year (from November until February). 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

12 Case Study 12  Small equipment room containing telecommunication racks, file servers or a midrange computer and it needs cooling. The hardware manufacturer recommends controlled conditions of 22  C  2  C and a relative humidity of 50%  5%.  Usually, a package air conditioning system is used in order to cool the room to the desired condition.  The cost of electrical energy is increasing because of the increasing prices of the oil and the high demand on the oil and the shortest resources of energy.  This fact was the main motivation for many researchers and scientific people to look for a method for saving energy. The new scientific work was resulted developing the free cooling technology in air conditioning system.  This method is based on using the outside air when the ambient temperature decreases below the desired inside temperature. Since the equipment room contains some telecommunication devices such as servers and computers, its temperature is usually high. 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

13 Technical Data (1) 13 Model Evaporator Data AMBIENT TEMEATURE  F Air Flow Rate On Coil Total Capacit y Sensible Capacit y Total Capacity Sensible Capacity Total Capacity Sensible Capacity Total Capacity Sensible Capacity Total Capacity Sensible Capacity Total Capacity Sensible Capacity DBDB WBWB CFM FF FF MBH PWM PWM PWM PWM PWM PWM nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

14 Technical Data (2)14 PWM Model Power Supply CompressorCFMEFM Nominal Motor Power HP(Kw) No. LRA (Each ) (AMP ) RLA (Each ) (AMP ) Motor (Kw) No. FLA (Each ) (AMP ) Motor (Kw) No. FLA (Each ) (AMP ) PWM V/1 ph/50 Hz 2(1.49) PWM 252.5(1.87) PWM 333(2.24) PWM V/3 ph/50 Hz 3.5(2.61) PWM 484.5(3.36) PWM 585(3.73) nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

15 Technical Data (3) 15  The electrical data for power supply are: 1.Compressor: Nominal Motor Power = 4.5 HP = 3.36 kW. 2.Condenser for Motor = kW. 3.Evaporator for Motor = kW.  Total electrical Input power = Motor Power for Compressor + Condenser + Evaporator = = 3.75 KW.  The Coefficient of Performance = COP = 13.69/3.75 = nd ICTEA, January 3 - 6, 2006, Al Ain, UAE  Room Volume = 3.0 m  2.5 m  2.5 m  Air flow rate for evaporator = 2000 cfm.  Cooling capacity of air conditioning system = 4.0 ton cooling load.  The outside ambient temperature at Zarka city was taken as 95F (35C)

16 Ambient Temperature 16 A comparison between the monthly average of minimum and maximum temperature values of Zarka city as a function of months 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

17 The Cost of Operating A/C Without Free Cooling 17 Cost of 1 kWh electricity = 0.05 JD Number of operating hours for A/C in April day is 12 hours. Total number of operating hours in April for A/C is 30 * 12 = 360 hours The cost of 360 hours per 1 kWh power = 360 * 0.05 = 18 JD Since our selected A/C has a total input electrical power of 3.75 kW, Cost in April month = 30 days * 12 hours * 0.05 JD * 3.75 kW= 67.5 JD 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

18 Cost of Operating Evaporator Fan Without Free Cooling 18  Normally, the air conditioning unit in JTC is permanently operated and therefore the evaporator fan will continue work during the time which the compressor is not working.  The electrical power for evaporator motor = kW.  The evaporator fan will be worked 12 hours more in April month, therefore: Cost in April for evaporator fan = 30 days* 12 hours*0.05 JD*0.147 kW = 2.64 JD 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

19 Total Cost of A/C Without Free Cooling 19  Total cost of A/C in April month that operates 24 hours per day (12 hours complete operation and 12 hours evaporator fan only) is: = JD  Total yearly cost = Sum of total electricity cost during 12 months = JD 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE Total electricity cost of the selected A/C in addition to the cost of the evaporator fan at different months.

20 Cost of Operating A/C with Free Cooling 20  No. of operating hours for A/C in April in the presence of free cooling is 5 hrs/day  Total number of operating hours in April for A/C is 30 * 5 = 150 hours  The cost of 360 hours per 1 kWh power = 150 * 0.05 = 7.5 JD  Since our selected A/C has a total input electrical power of 3.75 kW, therefore the total cost of operating such a unit during April is Cost in April month = 30 days * 5 hours * 0.05 JD * 3.75 kW= JD 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

21 Cost of Operating Evaporator Fan with Free Cooling 21  The electrical power for evaporator motor = kW.  The evaporator fan will be worked 19 hours more in April month, therefore  Cost in April for evaporator fan = 30 days * 19 hours * 0.05 JD * kW = 4.19 JD 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

22 Total Cost of A/C without Free Cooling 22  The total cost of A/C in April month that operates 24 hours per day (5 hours complete operation and 19 hours evaporator fan only) is JD JD = JD  Total yearly cost = Sum of total electricity cost during 12 months = JD 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE Total electricity cost of the selected A/C in addition to the cost of the evaporator fan at different months

23 Total Cost With & Without Free Cooling 23  Total cost of operating A/C without free cooling = JD/ year.  Total cost of operating A/C unit with free cooling = JD/year.  The difference in the cost = – = JD.  % of money saving = / = 42.6%  This result means that 42.6% from the total cost of electricity can be saved each year in the case of using free cooling technique.  The capital cost of the A/C system with dampers for free cooling is higher than the normal A/C by about 500 JD.  This means that the difference in the Capital Cost can be recovered after one year from operation because the running cost of operating A/C with free cooling is JD less than the normal A/C 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

24 Total Cost With & Without Free Cooling 24 A comparison between the total electricity cost for operating air conditioning unit in the case of presence or absence of free cooling at the desired location and the required cooling capacity. 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

25 Total Cost With & Without Free Cooling 25 The Coefficient of Performance (COP) can be reached a very high value in the case of free cooling. As it is known, the coefficient of performance is defined as the ratio between the output cooling load and input electrical power. The output cooling load is the same in the two cases which are the presence of free cooling air conditioning unit and in the absence of free cooling. But, the electrical input power is reduced in the case of free cooling and the input power is only the power needed for evaporator fan. Therefore, the calculated value of the coefficient of performance in the presence of free cooling is:  The Coefficient of Performance = COP = 13.69/0.147 =  While in the absence of free cooling The Coefficient of Performance = COP = 13.69/3.75 = 3.65 = = = nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

26 Conclusions 26 The main purpose of this project to study the utilizing of free cooling in the A/C system especially for the rooms which contains some heat generating sources and they needs to be cooled all days around the year. During cool weather, the outside ambient temperature can help save energy in A/C systems. The 4 ton cooling load in JTC buildings represents about kW of cooling load, which is effectively provided with about 3.75 kW of electrical consumption for a COP of However there are periods of the year where cooling ambient temperature can be utilized to provide nearly free cooling and the COP > 90 – where the only energy consumption is from the use of evaporative fans. The A/C system uses “free” cooling during cold weather without the requirement to run a compressor. The compressor of A/C is shut off during this period, thereby saving energy. The cost for damper installation can be recovered in less than two years. 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE

27 End of presentation 27 2nd ICTEA, January 3 - 6, 2006, Al Ain, UAE  Everything should be made as simple as possible, but not simpler. Albert Einstein ( )  A theory is something nobody believes, except the person who made it. An experiment is something everybody believes, except the person who made it. Albert Einstein ( )  It is a capital mistake to theorize before one has data. Insensibly one begin to twist facts to suit theories instead of theories suit facts. C. Doyle Thanks for you attention, شكرا جزيلا لحسن استماعكم The Final Conclusion !


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