Using M-15 filter media and the requirement of 60 cfm per person of outdoor air for the case of a designated smoking area for 53 persons, design a filter and air-circulation system allowing the actual outdoor air rate to be reduced to 20 cfm per person. Assume outdoor and recirculated air are mixed before filtering and insignificant amounts of outdoor air contaminants are present. The filter media must have a gravimetric efficiency of 80 percent in the
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- Consider a boiler that burns sub-bituminous coal. The boiler has a cyclone furnace burner and has a thermal capacity of 500 MW. Consider the calorific value of coal at 25 MJ/kg. Obtain the annual emissions of mercury emanating from this boiler with the specified control system; Report your result in kg/year. Also, estimate the emissions if the boiler did not have an emission control system (kg/year). Finally, report the % reduction in emissions obtained from the control equipment that the boiler has. Emission factor Hg= 6.88x10^-5 kg/J Emission factor Hg uncontrolled= 4.15x10^-5 kg/Mgarrow_forward1. A variable-air-volume cooling system delivers air to a controlled space maintained at 24 C db and 17 C wb. Under design conditions, the total cooling load is 60 kW with a sensible heat factor of 0.60, and the supply air temperature is 16 C db. At minimum load, about 7.5 kW with SHF of 0.80, the air quantity may be reduced no more than 75% by volume of the full load design value. Calculate the minimum volume of air to be supplied to the space at minimum load, cu.m/min.arrow_forwardAn assembly hall was to have an air conditioning unit installed which would be maintained at 24°C dry bulb and at 50% Relative humidity. The unit delivers air at 14°C dry bulb and the calculated sensible heat load is 140 kW and the latent heat load is 50 kW. Twenty five percent by weight of extracted air is made up of outside air at 32°C dry bulb and 18°C welt bulb temperatures while 75% is extracted by the air conditioner from the assembly hall. The atmospheric pressure is 100 kPa and Rair is 287.08 j/kg-k. Using Psychrometric chart determine; a. The mass of circulating air b. The amount of moisture pick-up in the space c. The capacity of the supply fan d. The air conditioning refrigeration capacity in TOR e. The dry bulb temperature entering the air conditionarrow_forward
- Q.1 An air conditioning system supplying air to a space with a sensible heat load of 14 kW and a latent heat load of 9 kW has a cooling coil and a bypass path as shown schematically in Fig. The db- temperature of the space is maintained at 26°C. The dry air mass flow rate of supply air is 1.2kg/s. Outdoor ventilation air at 34°C db-temperature and 50% relative humidity is introduced into the system with a dry air mass flow rate of 0.26 kg/s. The air leaving the cooling coil is fully saturated at a db-temperature of 6°C. The pressure is constant at 101.3 kPa. Determine db-temperature and relative humidity of the supply air to the space, (ii) (i) (ii) (iv) wb-temperature of the space, temperature of the air entering the cooling coil, and refrigeration capacity of the cooling coil.arrow_forwardAn auditorium to be air-conditioned for the following conditions, Outdoor dry-bulb temperature 40 °C Outdoor wet-bulb temperature 20°C Expected comfort condition 20 DBT 60%RH Seating capacity of the auditorium 1500 persons Air supplied from outdoor 0.3 m¥min per person fthe required condition is achieved first by adiabatic humidification and then by cooling, determine () the capacity of the cooling coil in tonnes and (i) the capacity of humidifier in kg/h.arrow_forwardA spray drier is used to dry skim milk to a final moisture content of 5.00%. The air entering the drier is 110°C, is heated from ambient air at 26.0°C and 80.0% RH. The flow rate of hot air entering the dryer is 1000 m3 dry air/min. The skim milk enters the dryer at 45.0°C with 55.0% moisture content and the exit temperature is 55.0°C. The specific heat of product solids is 2.00 kJ/kg dry solid-°C. The heated air leaves the system at 5.00°C above the product temperature. Determine: a. the %RH of air leaving the dryer; and b. the production rate of the moist product leaving the dryer. (Note: Obtain necessary properties of air using the psychrometric chart given to you; All moisture content is on wet basis)arrow_forward
- Air enters a cooling coil at the rate of 5000 cfm (2.4 m3/s) at 80 F (27 C). db, 68 F (20 C) wb and sea-level pressure. The air leaves the coil at 55 F (13 C) db, 54 F (12 C) wb. (a) Determine the SHF and the apparatus dew point. (b) Compute the total and sensible heat transfer rates from the air.arrow_forwardEXAMPLE 5: 1.5 m 3 s -1 of moist air at a state of 28C dry-bulb, 20.6C wet-bulb (sling) and 101.325 kPa flows across a cooler coil and leaves the coil at 12.5C dry-bulb and 8.336 g per kg of dry air. Determine (a) the apparatus dew point, (b) the contact factor and (c) the cooling load.arrow_forwardA furnace heating unit has an airflow of 2,500 CFM. The heating coil entering temperature is 35°F dry bulb temperature with a relative humidity of 30%. the furnace heating coil leaving temperature is 80°F dry bulb temperature. Plot the points and the process line on the psychrometric chart. Find the sensible, latent, and total loads of the coil. (hint: heating does not change the moisture content in the air) OUTSIDE AIR 2,500 CFM 35°F DRY BULB TEMP. 30% RELATIVE HUMIDITY FURNACE 80°F DRY BULB TEMP. 2 SUPPLY AIRarrow_forward
- While evaluating the performance of a boiler it is observed from flue-gas analysis that %02 content of flue gases entering and leaving a rotary air heater are 7.0% and 10.5%, respectively. Determine the percentage infiltration of ambient air.arrow_forwardAtmospheric air, which is a mixture of dry air and water vapour, is supplied into ducting with a cooling coil. Initially it has a relative humidity of 0.57, volumetric flow rate of 0.72 mis and temperature of 17°C. The atmospheric air is then passed over a cooling coil such that the temperature drops to 6°C. As this is below the dew point, the water vapour condensates after cooling coll and the air leaves in a saturated state. Assuming the barometric pressure of atmosphenic air to be 1.01325 bar, determine the folowing quantities in question parts () to (vi): (1) Partial pressure of water vapour in the air and water vapour mixture entering, Pularrow_forwardA laboratory space to be maintained at 24oC DB and 50% RH experiences a sensible-cooling load of 42 kW and a latent load of 18 kW. Because the latent load is heavy, the air-conditioning system is equipped for reheating the air leaving the cooling coil. The cooling coil has been selected to provide outlet air at 9 oC and 95% RH. What is (a) the air rate and (b) the temperature of supply air? Air pressure is 101.325 kPaarrow_forward
- Refrigeration and Air Conditioning Technology (Mi...Mechanical EngineeringISBN:9781305578296Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill JohnsonPublisher:Cengage LearningPrinciples of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning