LAB NO.
: 8 LAB TITLE : Title: Cooling Tower DATE :
LEVEL OF OPENNESS : 1
CLASS : EC110 5F
GROUP LEADER: STUDENT NO: GROUP MEMBERS
NO. NAME STUDENT NO. SIGNATURE REMARK
1. Muhammad Izz Mirza bin Mohd Isa 2014886638 2. Nur Alya Khairina binti Shaiffullail 2014880742 3. Nur Amelia Syarina binti Amidin 2014224262 4. Nik Muhamad Harith bin Nik Rosli 2014421554 5. Muhammad Akmal bin Yahya 2014894858 ASSESSMENT OF THE LAB ACTIVITIES
NO. ELEMENT TO ASSESS STUDENT
1 2 3 4 5
INDIVIDUAL IN-LAB ACTIVITIES 1 PUNCTUALITIY
2 DISCIPLINE (DRESS CODE,SAFETY SHOES,SAFETY REGULATIONS)
3 KNOWLEDGE ON OPEN ENDED LABORATORY GROUP IN-LAB ACTIVITIES
4 LEADERSHIP SKILL 5 COMMUNICATION 6 ORGANISATION/TEAMWORK LAB REPORT 7 INTRODUCTION 8 BASIC CONCEPTS
9 SUMMARY OF PROCEDURES/ METHODS 10 ANALYSIS AND INTERPRETATION OF DATA 11 DISCUSSION OF RESULT
12 CONCLUSION LECTURER’S
SIGNATURE:
REMARKS:
ECM 346 – BUILDING SERVICES
THE REPORT MUST BE SUBMITTED 1 WEEKAFTER THE COMPLETION OF THE LAB.
Faculty of Civil
Engineering
UiTM Pahang
1.0 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.
2.0 Objective
The objective of the laboratory session is:
3.0 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 wet-bulb 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 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.
4.0 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
5.0 Apparatus
The Hilton Bench Top Cooling Tower fitted with the Packing Characteristic Column, H 891 bench cooling tower, Stop watch
6.0 Procedures
1. The fan inlet damper was fully open andthe water flow was set to its maximum 2. Add water if necessary
3. The water heater was switch to give a heat input of 1.0 or 1.5 kW
4. The orifice differential pressure, water flow rate and all temperature was observed and recorded
5. The observation was repeated at a number of lower water flow rates down to about gm/s.
7.0 Data Acquisition Test No. 1 2 3 4 Packing Installed B B B B Packing Density m-1 110 110 110 110 Air Inlet Dry Bulb
° C
t 1
32.4 32.5 32.7 32.5 Air Inlet Wet Bulb° C
t 2
27.3 26.8 26.3 25.7 Air Outlet Dry Outlet° C
t 3
27.8 29.3 30.2 31.2 Air Outlet Wet Outlet° C
t 4
28.0 29.1 30.1 31.2 Water Inlet Temperature° C
t 5
26.6 30.9 34.4 38.2 Water Outlet Temperature° C
t 6
26.1 27.1 27.7 28.2 Orifice DifferentialH 2 O
X
16 16 16 16 Water Flow Ratemw
gms
−1 38 38 38 38 Cooling LoadkW
Q
0 0.5 1.0 1.58.0 Discussion
We have conducted four test on cooling tower in which we obtained a different values of each test. For water cooling tower experiment, there are several parameters that can be adjusted to observe its effects on the evaporation of water. The parameters are temperature and flow rate of water and cooling load. In this experiment, we choose the cooling load as variable while water flow rate as constant parameters. We have determine the value for air inlet dry bulb are greater than the values of air outlet dry. It shows that the values is decreasing from the inlet air to the outlet air. The value of water inlet temperature are higher than the value of outlet water temperature.
In the cooling tower, water is cooled by the process known as evaporation. In the process, heat energy is being transferred between the water and air which having different temperature. As the energy in the water molecules is transfer to the air flowing through the water, the bond of the water molecules becomes weaker then it will slowly evaporate to the air. It can be prove from the result of this experiment, whereby the water outlet temperature is lower than the inlet.
From the data obtained at the end of the experiment, changes in heater power will affect the energy being transferred within the system and surrounding. Larger heater power will cause higher temperature in water. As for this experiment, the temperature of the water is assumed higher than the air flowing through the system (without considering the changes in heater power). As the difference in the temperature between the water and air increase, the heat energy being transferred rate is therefore higher than the lowered heater power.
TABLE 2 : FACTORS AFFECTING COOLING TOWER PERFORMANCE
Factors Description
1. Capacity - Heat dissipation and circulated flow rate are not sufficient to understand cooling tower performance
- For example, a cooling tower sized to cool 4540m3/hr through
a 13.9°C range might be larger than a cooling tower to cool 4540m3/hr through 19.5°C range
2. Range - The range at the exchanger is determine entirely by the heat load and the water circulation rate through the exchanger and on to the cooling water
- Cooling towers are usually specified to cool a certain flow rate from one temperature to another temperature at a certain wet bulb temperature
3. Heat Load - The heat load imposed on a cooling tower is determined by the process being served
- Process heat loads may vary considerably depending upon the process involved
4. Air
Compressor
- There are various types of air compressor and its values of heat rejection
9.0 Conclusion
As the difference in temperature between the water and air increase, the rate of heat energy being transferred is higher than the lowered heater power. Therefore, it can be said that heater power is directly proportional to heat energy transfer rate. Hence, this experiment has been a success since the objectives of the experiment were achieved and we have gained knowledge regarding to the water cooling tower operation.
10.0 References
1. http://www.p-a-hilton.co.uk/products/H893-Bench-Top-Cooling-Tower
2. http://spxcooling.com/coolingtowers
