Mechanical Engineering Project: Cooling System and Air Quality Design

This project details the design of a cooling system and the maintenance of indoor air quality for a single residential dwelling. The design work is divided into three parts: cooling tower pump design, indoor air quality determination, and psychometric analysis. The cooling tower pump design considers parameters such as pump head, flow rate, and pipe dimensions. The indoor air quality section focuses on determining and maintaining critical parameters for optimal air quality. The project utilizes psychometric charts to analyze air temperature, humidity, and mixing points, calculating outside air sensible and latent heat requirements. The design process incorporates standards like AS 1668.2-2012 and considers factors like room dimensions, window, roof, and floor properties. The project also includes the selection of indoor and outdoor units based on power requirements and airflow rates, providing a comprehensive approach to designing an effective and efficient cooling system.

DESIGN OF THE COOLING SYSTEM AND INDOOR AIR QUALITY OF
A SINGLE RESIDENTIAL DWELLING
Prepared By: (XYZ)
Dated: 8th Sept 2017
INTRODUCTION
Residential dwellings are to be properly designed in order to serve the intended purpose; mainly
providing conducive environment for the occupants. Admittedly, a properly designed dwelling
will offer a long-lasting impact on the dwellers and will even affect the behavior of the occupants
in the long run. Notably, there are building services that must be incorporated into the building to
meet the design requirements. The room air quality is therefore a fundamental aspect of the
building services engineering. During summer, when room temperatures are likely to hit
unimaginable highs, it is often imperative to provide artificial cooling to the room. Now, a
cooling tower will be used for this purpose. This report presents a technical design work on the
said building services engineering facility. Top on the list, is the fact that the room thermal
performance must be in tandem with the environmental conditions of the area in which the
building is to be seated. Majorly, the design work is split into three parts; the cooling tower
pump design; Deriving and maintaining the indoor air quality and building psychometrics where
aspects such as air temperature, humidity and general air quality are considered. In designing the
cooling tower pump, the general dimensional characteristics of the building is needed. Notably,
the information that has been provided to facilitate the design include: the suction pipe nominal
diameter is 200mm with the cooling tower being on the 6th floor. The elevation to 6th floor from
basement is 20m. The suction side has the globe valve, strainer, a horizontal pipe run 200mm in
diameter; while the discharge side has got the gate valves, long radius 90o elbow; 1 off globe
valve, 1 off strainer, 20m long 200mm diameter pipe run. The cooling tower is to be installed in
a residential single dwelling with 3 bedrooms, 1 dining, 1 kitchen, a home office and a toilet.
Overly, the basic size of the house plan is 14 000mm x 15 000mm. On the other hand, the second
and third portion of the project will be to determine the critical parameters that must be
maintained in a room for proper indoor air quality. Psychometric analysis will come in handy in
this section. Specifically, the following are determined: R and U values for the window, roof and
floor which would then assist in determining the values of Q(sh); Q(lh) and outside airflow
required per area. Here, the design standard AS 1668.2-2012 shall be used. Lastly, we shall use
the psychometric chart to determine the outside airflow indoor condition point; mixing point Db
and Wb hence outside air SH and LH will be calculated based on the provide room temperature.
Importantly, therefore, the design work is aimed at deriving a workable system within the
interiors of the room. Certainly, improvements to the system will be implemented only after
several test trials are done.

DESIGN WORK
Part 1: Cooling tower pump
The following parameters are determined: Pump head, Q, NPSH, diameter, Power, pump
selection, Head loss, water vapor pressure, Static head and atmospheric pressure:
Pump head= suction head +delivery head= 20m
Q=
Part2: Indoor Air Quality
Check the attached excel file
Part3: Psychometric chart
Based on provided catalogue (ducted split unit),
(i) Select your indoor and outdoor unit and power requirement
Indoor power requirement=4.17kW
Rated power requirements= 12.5kW
Airflow rate= 900
Weight (indoor)= 65kg
Weight(outdoor)= 98kg
(ii) On psychrometric chart show the outside air point (1)
(iii) On psychrometric chart show indoor condition point (2)
(iv) On psychrometric chart show the mixing point (3)
(v) Calculate mixing point Db and WB
(vi) Provide all values (DB, WB, RH, h, specific volume, moisture content of the points 1,
2, 3 including the units. 11. Based on provided room temperature calculate the
required outside air SH and LH.