While having good air quality is of paramount importance, but doing so, while saving energy is the sustainable need of the hour. Consistent Engineering Consultants participated in the HVACR Saudi Expo held at Riyadh International Exhibition Centre from 11th to 13th of March where our Mr. Ahmed Zeb, our Director of Operations presented a talk on Energy Optimisation and Building Ventilation Systems. He spoke about the need for energy conservation, energy optimisation and its role in structuring the building ventilation systems. Here's the presentation.

1. ENERGY OPTIMIZATION & BUILDING
VENTILATION SYSTEMS
MR. AHMAD ZEB,
DIRECTOR - OPERATIONS,
CONSISTENT ENGINEERING CONSULTANTS
Organised by

2. 1
List of Contents
 Introduction
 Necessity of IAQ
 Energy Statistics
 Types of Ventilation Systems
 Criteria for Designing Ventilation Systems
 Factors Impacting on Energy Consumption due to Ventilation Optimization Techniques
 Optimization Techniques
 Energy Recovery Ventilation System
 Case Study Statistics
 Energy Optimization: New Building vs Retrofit
 The Consistent Perspective
 Key Takeaways

3. 2
Introduction
• Working towards a sustainable future is no longer a privilege today, but a necessity.
• Meeting the energy demands of the future necessitates conservation, recovery and renewability
• Indoor Air Quality (IAQ) is a vital component in order to maintain a healthy indoor environment
and keep-in check the pollutants in the built environment.
• Ventilation systems are installed to achieve good IAQ.

4. 3
Necessity of IAQ
PM2.5 , PM 10 AND O3 Hazard Scale

5. Energy Statistics
• HVAC systems account for about 70% of
energy consumption in typical GCC region
buildings.
• Of this, approx. 30%, i.e. 21% of the total
energy consumption is accounted for the
ventilation system.
• By 2050, the population of the world will have
grown to 9.7 billion, a staggering 70% of which
will be living in urban areas
• Thus, stringent action is required to both
conserve and recover energy; and ventilation,
being 21% of energy consumption, needs to be
optimized for the same.
4

6. 5
Types of Ventilation Systems

7. 6
Types of Ventilation Systems

8. 7
Criteria for Designing Ventilation Systems
Natural ventilation:
Natural ventilation shall be acceptable for low rise building & Vilas as per ASHRAE 62.2-2016.
Mechanical ventilation (as per ASHRAE 62.1-2019 & 62.2-2016):
1. Fresh air for each space shall be considered with summation of L/s/m2 & L/s/person.
2. Diversity factor considered for occupancy as per ASHRAE standard. Overall fresh air requirement optimized for
FAHU sizing.
3. CO2/Occupancy sensors shall be provided for demand control ventilation to achieve energy savings.
4. Recirculation of air from clean areas to dirty areas shall be transferred as Fresh air compensation (Class I, II, III to
IV) in order to optimize the FAHU sizing.
5. Free cooling shall be considered during winter season for energy savings.
6. Scheduling shall be established in line with end user to provide ventilation as well as to retain building under
positive pressure.
7. All FAHU motors shall be equipped with VFD’s for optimization of energy consumption.
8. All FAHU shall be heat recovery type such as Dual heat recovery wheels for residential, commercial, hospitality &
health care.
9. Energy recovery ventilators shall be used for low volume applications such as villas etc.

9. 8
Factors Impacting on Energy Consumption due to Ventilation.
1. Continuous operation of OAHS to cater space requirement (No DCV)
2. Unscheduled Ventilation System
3. Decentralized Ventilation system
4. Centralized Ventilation system without energy recovery
5. Improper Maintenance of equipment

10. 9
Optimization Techniques
• Demand-Controlled Ventilation - Demand-Controlled Ventilation allows the system to accommodate
times when the room is partially occupied, with occupancy sensors, CO2 sensors, or a time-of-day
schedule.
• Heat Recovery - Air heat-recovery systems are most often employed to preheat and/or pre-cool
ventilation air to reduce the system load. Simply put, air-based heat-recovery systems use the
exhaust/relief building air to temper the OA before it is heated or cooled by putting the two airstreams
through a heat exchanger. Some heat-recovery ventilators, often referred to as energy-recovery
ventilators.

11. 10
Optimization Techniques
• Variable air volume (VAV) is a type of HVAC system. Unlike constant air volume (CAV) systems,
which supply a constant airflow at a variable temperature, VAV systems vary the airflow at a constant
temperature. The advantages of VAV systems over constant-volume systems include more precise
temperature control, reduced compressor wear, lower energy consumption by system fans, less fan
noise, and additional passive ventilation
• Constant air volume (CAV) is a type of HVAC system. In a simple CAV system, the supply air flow
rate is constant, but the supply air temperature is varied to meet the thermal loads of a space. Most
CAV systems are small, and serve a single thermal zone. However, variations such as CAV with
reheat, CAV multi-zone, and CAV primary-secondary systems can serve multiple zones and larger
buildings.

12. Energy Recovery Ventilation Systems
• Energy recovery ventilation systems recover the heat
from the return air from the building (from toilets,
general extract, etc.) prior to exhausting it to the
atmosphere.
• Helps in precooling the ambient air and reduces the
cooling capacity of the equipment and indirectly the
overall power consumption
• Reduces energy wastage by recovering the heat
from the extract from buildings
• Minimizes energy wastage and increases building
performance
• Economizes the building operational cost and
improves building performance
11

13. Energy Recovery Ventilation Systems (contd.)
• Majority of the buildings in Dubai were built during
the late 90s - early 00s, and thus lack of advanced
technological features of today. Ex: Constant speed
compressors, air handlers without heat recovery
sections, central fans etc.
• Buildings constructed 10-15 years ago have
ventilation systems in which the fresh air is supplied
from a central fan or FAHU however, the extract was
locally/centrally exhausted.
12

14. Energy Recovery Ventilation Systems (contd.)
Heat Pipe Arrangement
13

15. Energy Recovery Ventilation Systems (contd.)
Sensible Wheel with Heat Pipe Arrangement
14

16. Energy Recovery Ventilation Systems (contd.)
Enthalpy and Sensible Wheel
15

17. Case Study Statistics
15
DESCRIPTION
FRESH AIR HANDLING UNIT (FAHU) CONFIGURATIONS
WITH COOLING
COIL ONLY
WITH HEAT
PIPE
WITH SENSIBLE
WHEEL & HEAT PIPE
ENTHALPY +
SENSIBLE WHEEL
Fresh Air (L/s) 5000 5000 5000 5000
Extract Air (L/s) - - 4000 4000
Cooling Coil
Capacity (kW)
442 360 192 178
Power Input (kW) 253 217.5 122 109
Approx. Annual
Power Consumption
(kW-h)
1329768 1143180 641232 572904
% Approx. Energy
Savings against
Normal FAHU
Configuration
- 14.66% 49.89% 56.92%

18. Energy Optimization: New Buildings vs Retrofits
17
New Buildings:
1. Demand Control Ventilation
2. Diversity on Ventilation system by proper utilization of ASHRAE standards and use of
CAR (Constant Air Regulator), ZRT (Zone register terminal), VAV (Variable air volume)
3. ERVS (Energy recovery ventilation system)
4. Free cooling with ambient sensor
5. Use of VFD’s
Retrofit:
1. Implementing ERVS as a Retrofit Scheme
2. Evaluating options of converting Decentralized Ventilation Systems to Centralized
Ventilation Systems

19. 19
The Consistent Perspective
• Energy Recovery Ventilation Systems can play an important role in reducing Energy
Wastage in Retrofit Projects
• ERVS drastically helps improve Building Performance, contributing to overall energy-
efficiency and sustainability
• All stakeholders must work to adopt ERVS, with legislations specifying this for all forthcoming
retrofit projects
• Consistent Engineering Consultants has always believed in being ahead of the curve, and
adopted a number of energy-efficient measures in its retrofit as well as new building projects

20. 19
Key Takeaways
01 Owners/Operators
Reduces Energy Bills and System Operating Costs
Improvised Building Performance
02 Designers
Responsibility to design Sustainable Buildings by detailed engineering.
03 Contractors
Key Stakeholder responsible to deliver the Dream Project to Owners.
04 Users
Improved Indoor Air Quality (IAQ) for occupants
Improved Activity Levels for Occupants

21. Thank You for attending this presentation
Don’t forget to collect your CPD certificate at the event from CPD
collection area
Organised by