Building Description

Detailed building energy simulations have been carried out using a dynamic simulation program ESP-r. A base case building model of the representative building was developed. It was decided to adopt the building design from the ASHRAE 2018 design competition, to design an energy efficient project approaching ''Zero Energy'' building with minimized energy demand and incorporate locally available or building-installed renewable energy sources (RES).

The building that was studied is a 70,000 square foot (6,500 square meter), four story mixed use complex. It includes offices, retail stores, conference rooms, and hotels. The offices and administrative support spaces are open 11 hours per day (7-18) Monday to Friday and 5 hours per day (8-13) on satarday, retail open 13 hours per day (9-22) Monday to Saturday and 8 hours per day (11-19) on Sunday, hotels open 24/7.

Base Model Construction The wall was constructed from light brown brick of 10cm and light mix concrete of 15cm and 1.5 cm of gypsum board and the resultant U-value was 1.3W/m^2. It might seem unreasonable but as this project is to investigate potential of energy efficiency in developing countries where there are no building energy efficiency regulations in place, this was relevant. The roof and floor were also constructed using 20cm of dense concrete without insulation. The windows were constructed using double glazing with two 6mm clear float glass 76/71 (Visible transmittance 0.76/G-value 0.71 ) without blinds with an air gap of 12mm. The windows U-value is 2.8W/m^2.

The building occupancy information was not available, so it was assumed for each space type as per ASHRAE 62.1 standard with the details shown in the table below.

Building Occupancy

Space Type	Area (m^2)	Occupancy per 100 M^2	Total Occupancy
		First Floor
Retail	1255	15	188
Lobby	45	50	22
Service Rooms	-	-	8
			Total: 218
		Second Floor
Offices	903	5	45
Conference Rooms	95	50	48
Lobbies	53	10	5
Break Rooms	32	50	16
Storage	32	2	1
			Total: 115
		Third Floor
Hotel	-	-	60
		Forth Floor
Hotel	-	-	60
		Total Building Occupncy: 453 Persons

Internal heat gain is the sensible and latent heat emitted within an internal space from any source that is to be removed by air conditioning or ventilation, and/ or results in an increase in the temperature and humidity within the space. Benchmark values for internal heat gains are based on either surveys of measured internal heat gains from a number of buildings of particular types and usage, or empirical values found appropriate from experience, survey and considered good practice in the industry. [1]

Following sources are concerned in most cases:
• Occupants
• Lighting
• Office equipment and computers

Occupants

All active animal bodies including humans lose heat to their surroundings due to
their metabolic activity, which is related to the activity to subject is performing
(i.e. sedentary, sleeping, dancing etc…). The heat can be released as sensible or
latent heat. The sensible heat release is due to the higher temperature the
surface of the skin can have in respect to the surrounding environment, while the
latent heat is released by means of respiration and sweating.
The table below shows heat emissions from an average adult male in different states of activity in different buiding spaces.

Occupants Heat Gain

Space Type	Occupants	Activity	Sensible Heat Gain (W/person)	Latent Heat Gain (W/person)	Total Sensible Heat(W)	Total Latent Heat(W)
Retail	188	Standing, Light Work, Walking	75	55	14,100	10,340
Lobby	22	Walking, Light Work	75	55	1650	1210
Service Rooms	8	Light Work	75	55	600	440
				Total First Floor	*16,350*	*11,990*
Offices	45	Seated, Very Light Work	70	45	3150	2025
Break Room, Resturant	16	Sedentary Work	80	80	1280	1280
Lobby	5	Walking, Light Work	75	55	375	275
Conference Rooms	48	Seated, Very Light Work	70	45	3360	2160
Storage	1	Meduim Work	75	75	75	75
				Total Second Floor	*8,240*	*5,815*
Hotel Third Floor	60	Seated, Very Light Work	70	45	4200	2700
Hotel Forth Floor	60	Seated, Very Light Work	70	45	4200	2700
	Total Occupants Sensible Heat Gain:	32,990 W	Total Occupants Latent Heat Gain:	23,205 W

Lighting

All the electrical energy used by a lamp is ultimately released as heat. The energy
is emitted by means of conduction, convection or radiation. When the light is
switched on the luminaire itself absorbs some of the heat emitted by the lamp.
Some of this heat may then be transmitted to the building structure, depending
on the manner in which the luminaire is mounted. The radiation energy emitted
from a lamp will result in a heat gain to the space only after it has been absorbed
by the room surfaces. This storage effect results in a time lag before the heat
appears as a part of the cooling load.
In determining the internal heat gain due to artificial lighting the following must
be known:

• Total electrical input power

• Fraction of heat emitted which enters the space

• Radiant, convective and conductive ratio of the heat emitted by the
lighting system

In the base model, flourescent lighting was used with a radiative fraction of 0.6 and a convective fraction of 0.4 and the lighting power densities that were used are as per ASHRAE Fundamentals 2017 standard shown in the table below.

Lighting Power Densities (LPD)

Space Type	LPD (W/m^2)
Sales Area	15.5
Enclosed Office	12
Office Open Plan	10.6
Lounges/Break Rooms	7.9
Storage Rooms	13.3
Corridor	7.1
Conference Room	13.3
Lobbies	9.7
Hotel Guest Rooms	12
Hotel Lobby	11.4

Equipment

Equipment such as computers in offices result in heat gains to the room equal to the total power input. The internal heat gains can be estimated from basic data but care must be taken to allow for diversity of use, idle operation and the effects of energy saving features of the equipment.

Heat Gain for Generic Appliances. The average rate of appliance energy consumption can be estimated from the nameplate or rated energy input qinput by applying a duty cycle or usage factor FU. The ratio of heat gain to appliance energy consumption may be expressed as a radiation factor FR, and it is a function of both appliance type and fuel source. The radiation factor FR is applied to the average rate of appliance energy consumption, determined by applying usage factor FU to the nameplate or rated energy input.Thus, sensible heat gain qs for generic electric, steam, and gas appliances installed under a hood can be estimated using one of the following equations:

qs = qinput* FU*FR

qs = qinput* FL

where FL is the ratio of sensible heat gain to the manufacturer’s rated energy input.[2]

Equipment Heat Gains

Diversity Factor

Diversity factor accounts for the occupants behavior as not all equipment and computers will be turned on at the same time and not all the hotel rooms will be occupied at the same time.

So a diversity factor for the offices was taken to be 0.6 for the office equipment and the occupants casual gains.[3]

A similar factor was used for the hotel to account for the occupants behaviour in the equipment use, lighting use and occupants casual gains.

The same factor was used in the retail floor to account for the plug-in loads and occupants casual gains.

Ventilation

Ventilation is the intentional introduction of outside air into the space by using fans. The purpose of ventilation is to remove the product of respiration and space contaminants such as smells, water vapor, gases, fumes, and vapors of industrial processes. In general, the ventilation system must supply fresh air to change the room air sufficiently so that smells, gases, and contaminants are removed.

The minimum outside fresh air requirements for mechanical ventilation during occupied times* are shown in the table below

Ventilation

*Outside occupied times a ventilation rate of 0.25 ac/h was used.

Results

[1] CIBSE Guide A Chapter 6 ‘Internal heat gains’
[2] ASHRAE Fundamentals 2017
[3] Elharidi, A., Tuohy, P. and Teamah, M. (2018). The energy and indoor environmental performance of Egyptian offices: Parameter analysis and future policy. Energy and Buildings, 158, pp.431-452.

Address

16 Richmond St,
Glasgow
G1 1XQ

Contacts

Email:
esru@strath.ac.uk
groupproject8@outlook.com
Phone: +44 (0)141 552 4400

Links

https://www.strath.ac.uk/

Building Description

The building occupancy information was not available, so it was assumed for each space type as per ASHRAE 62.1 standard with the details shown in the table below. Building Occupancy

Address

Contacts

Links

The building occupancy information was not available, so it was assumed for each space type as per ASHRAE 62.1 standard with the details shown in the table below.

Building Occupancy