FAKULTI KEJURUTERAAN AWAM UNIVERSITI TEKNOLOGI MARA LABORATORY MANUAL
KAMPUS SAMARHAN 2 COURSE
BUILDING SERVICES
COURSE CODE
ECM 346
LEVEL OF OPENNESS
1
CATEGORY
PARTIALLY OPEN ENDED
DEGREE OF OPEN-ENDED (%)
33
PERIOD OF ACTIVITY
1 WEEK (WEEK 6)
TITLE
OPERATION SYSTEM AND MAINTENANCE OF AIR CONDITIONING - COOLING TOWER 1.1 Introduction Level 1 laboratory activity refers to condition where the problem and ways & means are guided and given to the students. However the answers to the assignment are left to the students to solve using the group creativity and innovativeness. The activity is to slowly introduce and inculcates independent learning amongst students and prepare them for a much harder task of open-ended laboratory activities. In this laboratory activity students will be exposed to the characteristic equation of the Hilton Bench Top Cooling Tower. 1.2 Objective The objective of the laboratory session is: To determine the characteristic equation of the Hilton Bench Top Cooling Tower. 1.3 Learning Outcomes
PREAMBLE
At the end of the laboratory activity, students would be able to: Understand the characteristic equation of the Hilton Bench Top Cooling Tower. 1.4 Theoretical Background Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere. Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wetbulb air temperature or, in the case of closed circuit dry cooling towers, rely solely on air to cool the working fluid to near the dry-bulb air temperature. Common applications include cooling the circulating water used in oil refineries, petrochemical and other chemical plants, thermal power stations and HVAC systems for cooling buildings. The main types of cooling towers are natural draft and induced draft cooling towers. The classification is based on the type of air induction into the tower. Cooling towers vary in size from small roof-top units to very large hyperboloid structures (as in the adjacent image) that can be up to 200 metres tall and 100 metres in diameter, or rectangular structures (as in Image 3) that can be over 40 metres tall and 80 metres long. The
©FKA, UiTM, SAMARAHAN (JUNE – OCT 2015)
FAKULTI KEJURUTERAAN AWAM UNIVERSITI TEKNOLOGI MARA LABORATORY MANUAL
KAMPUS SAMARHAN 2
hyperboloid cooling towers are often associated with nuclear power plants, although they are also used to some extent in some large chemical and other industrial plants. Although these large towers are very prominent, the vast majority of cooling towers are much smaller, including many units installed on or near buildings to discharge heat from air conditioning.
PROBLEM STATEMENT
Reproduces all the processes that are found in an industrial system serviced by a forced draught cooling tower. The unit incorporates a process load, circulating pump, packed column, water distribution, volume control system and fan. Standard instrumentation allows measurement of the air, circulating water mass flow rate and all end state temperatures using wet and dry bulb thermocouples. Evaporation rates under varying load and flow conditions can also be investigated. As a group you are required to determine the characteristic equation of the Hilton Bench Top Cooling Tower. The group must carry out the test following the procedures outline and subsequently analyse the data and present it in a proper technical format. 1.1 Apparatus The Hilton Bench Top Cooling Tower fitted with the Packing Characteristic Column. 1.2 Procedures 1. Fully open the fan inlet damper and set the water flow to its maximum
WAYS & MEANS
2. Switch the water heaters to give a heat input of 1.0 or 1.5 kW. 3. Allow temperature to stabilize. 4. Observe : i-
Orifice differential pressure
ii-
Water flow rate
©FKA, UiTM, SAMARAHAN (JUNE – OCT 2015)
FAKULTI KEJURUTERAAN AWAM UNIVERSITI TEKNOLOGI MARA LABORATORY MANUAL
KAMPUS SAMARHAN 2 iii-
All temperature
5. Repeat the observations at a number of lower water flow rates down to about 10gm s‾1, always allowing conditions to stabilize and making any temperature corrections necessary. 6. Partly close the air intake damper and repeat the foregoing at manometer reading of say 6 and 2 mm H2O. REMOVAL OF WET AND DRY BULB SENSORS 1. Remove the cap from the cable conduit at the back of the column and release sufficient thermocouple cable to allow withdrawal of the sensor. 2. Hold the end of the sensor to prevent rotation, then unscrew the black hexagonal gland nut to free the sensor. 3. Still holding the sensor, unscrew and withdraw the black hexagonal gland body. 4. Carefully withdraw the sensor, rotating it thought 900 so that wick clears the ports in the sensor hood. 5. When replacing the sensor, it is helpful if the wick clears the ports in the to clear the ports in the hood.
4 Results, Analysis and Conclusion RESULTS
The group is required to submit the technical report of the laboratory results highlighting the data acquisition process, analysis carried out and the relevancy of the set-out output to achieve the objective. The format of the report is left to the creativity discretion of the group. The report must be submitted 7 days after the completion of the test.
©FKA, UiTM, SAMARAHAN (JUNE – OCT 2015)
