Air Recirculation Through a Duct-Room System Lab Report

Running head: LAB REPORT 1 1
Air Recirculation Through a Duct-Room System
Student Name
Professor’s Name
University Name
Date

LAB REPORT 1 2
Abstract
The purpose of this laboratory was to examine air flow into a room and analyze the heat
losses during heating and cooling and the power consumed by the pre-heaters during operation
and explain the possible causes for the phenomena above. Two test A and B were conducted. In
test A, air was allowed to flow into the room via a duct and into the outlet whereas in test B. air
was allowed to flow into the room via a recirculated system. In test A, the inlet and the outlet
louvres were open while the recycle louvre was closed. On the other hand, in test B the inlet and
the outlet louvres were closed and only the recycle louvre was operational. The velocity of air
flowing into the room and the temperatures were measured using velocity meters and
temperature sensors respectively. It was observed that the temperatures were higher for test B
where a recirculated system was used compared to test A for there was no recirculation.

LAB REPORT 1 3
Contents
Abstract......................................................................................................................................................2
Introduction...............................................................................................................................................4
Methodology..............................................................................................................................................5
Equipment’s Used..................................................................................................................................5
Experimental Set-up..................................................................................................................................6
Assumptions...........................................................................................................................................7
Procedure...............................................................................................................................................8
Test A......................................................................................................................................................8
Test B......................................................................................................................................................8
Results and Analysis..................................................................................................................................9
Conclusion................................................................................................................................................12
References................................................................................................................................................14
List of Tables
Table 1: Results...............................................................................................................................9
List of Figures
Figure 1: The Assembled Simulator System...................................................................................6
Figure 2: Sectional View of the Simulator......................................................................................6
Figure 3: Computer Software Output..............................................................................................8

LAB REPORT 1 4
Introduction
Heat transfer is the process by which energy is transferred from a medium of low
temperature to a medium of high temperature (Serth & Lestina, 2014). The various forms of heat
transfer are conduction, convection, and radiation (Rathore & Kapuno, 2011). The basic
principle of heat flow is that when cold air is heated, it gets warm hence lowering its density
forcing it to move upwards, the denser air above flows down to occupy the space left by the less
dense air and in the process there is a continuous flow heat via convection (Arora, 2012). In
solids, the process occurs by thermal conductivity where heat from the hot point flows to the
cold point through the movement of electrons (Bejan, 2016). Radiation occurs in space, such as
when the sun heats the ground (Kaviany, 2011). The study of heat transfer aids in the analysis of
thermodynamic processes such as flow of air in a room and its efficiency (Gaskell & Laughlin,
2017). The thermodynamic systems are later used to design systems such as the cooling systems
and ventilations for domestic, commercial and industrial use (Kreith & Manglik, 2018).
In this experiment, heat flow from one end to the other end of an enclosed assembled
system is determined to simulate what would happen in a real environment. Heat transfer
between two surfaces is determined using the following equation below:
∆ QAB =m(CpB T B−C pA T A )
The mass flow rate “m” is determined as follows:
m=ρV =ρ Ac V avg (Kgm−3 )
The specific heat is determined by the equation below (Cao, 2010).
C p= 28.11+0.1967 x 10−2 T +0.4802 x 10−5 T 2−0.1966 x 10−9 T3
28.97
Where T is the temperature in Kelvin and Cp is in KJ/Kg. K (Tritt, 2005).