This is a recording of a presentation delivered by Qatar Green Leaders at the 2nd Annual Qatar HVAC Contracting Conference held at the Intercontinental Doha on 4th December 2017. The presentation addressed the interrelationships between HVAC design and various high performance goals as defined by LEED & GSAS rating systems.
Qatar Green Leaders
Green Building Certification Management (LEED / GSAS)
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CCXG global forum, April 2024, Brian Motherway and Paolo Frankl
The Role of HVAC in Achieving High Performance Goals
1. The Role of HVAC
Systems in Achieving
High Performance
Goals
Diaa El-Masry
Architect, PMP, LEED AP, GSAS CGP Practitioner
General Manager
Qatar Green Leaders
2. QATAR GREEN LEADERS
THE FUTURE IS
GREEN!
facebook.com/qgl.doha twitter.com/qgl2010 info@qatargreenleaders.com +974 5516 8239
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Introduction
It provides a quick guide on how to optimize
the parameters of the HVAC systems in order
to fill the gap between the code requirements
and green building goals.
The presentation focuses on the relation between HVAC and
green building performance, not only in energy savings, but
also in other aspects of green building such as IEQ & Water
Savings.
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Topics
1
Functions and performance
parameters.
2
International & local
codes.
3
HVAC system &performance criteria
in
LEED & GSAS.
4 Innovations & advancements.
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What defines a
HVAC system?
Heating, Ventilating, and Air Conditioning
(HVAC) equipment perform heating and/or
cooling for residential, commercial or industrial
buildings.
The HVAC system may also be responsible for
providing fresh outdoor air to dilute interior
airborne contaminants such as odors & CO2
from occupants & chemicals used for cleaning,
or other sources of contamination.
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Functions of
HVAC
System:
1
Providing optimal
thermal comfort.
2
Enhance the indoor air
quality.
3
Sustainable source as
a green building
element.
4
Efficiency and
economy
5
Air filtration and clean
air
Malfunction
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Building
HVAC
systems are
controlling…
• Heat
• Temperature
• Relative
humidity
• Air Speed
• Quality of Air
• Air
Contaminants
• Co2 level
Comfort Health
9. Regulation
s and
codes
HVAC systems are regulated
at different levels:
• International standards
• Local codes/building
regulations
• Green building codes
• Project spec`s /
developer requirements.
10. Common
Internationa
l Standards
Energy Standard for Buildings
Except Low-Rise Residential
Buildings.
ASHRAE standard
90.1
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Ventilation for Acceptable Indoor Air
Quality
ASHRAE 62.1
Thermal Environmental Conditions
for Human Occupancy
ASHRAE 55
CIBSE AM
Standard for the Installation of Air
Conditioning and Ventilating
Systems
NFPA 90A
Chartered Institute for Building
Science Engineers (Application
Manuals)
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Local Codes
& Building
Regulations
• Kahramaa Regulations
• QCS 2014
Section 22 - Air-conditioning refrigeration and
ventilation
Section 9 – Mechanical and Electrical Equipment
Section 7 – Green Construction
• QCDD (Qatar Civil Defense Department)
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[IP]
Integrative
Process
• Feasibility of different solutions
• Selection of preferred HVAC system types
• Integration of HVAC properties in Design /
Construction Documents
• Coordination between different disciplines,
optimize performance and maximize benefits.
…
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[EA]
Energy &
Atmosphere
• Demand Control
Ventilation
• Efficiency (COP/EER/EIR)
• Fan Operation Schedule
• Specific Fan Power (SFP)
• Commissioning of HVAC
Systems
Equipments
• Monitoring the Operation.
• Sub-metering the HVAC
energy Consumption
• Renewable Air
Conditioning System
(QCOOL).
[E]
Energy
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[WE]
Water Efficiency
• Conserve Cooling Tower Makeup Water.
• Utilize of Non-Potable Water for Cooling Towers
• Identify opportunities for additional water saving
• Reuse of Condensate Water
[W]
Water
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[IEQ]
Indoor
Environmental
Quality
• Demand Control Ventilation.
• Mechanical Ventilation
Capacity
• Thermal Comfort & Control
• Acoustic Quality & Control
• Building Flush-Out
Requirements
• Using High-Quality Filters
(MERV)
• Source Control Measures
• IAQ During Construction
[IE]
Indoor
Environment
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[RP]
Regional
Priorities
• Supporting the national economy
• Integration in urban context & reducing Visual
Impacts.
[CE]
Culture &
Economic Value
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GSAS
• Total GSAS criteria 56
• HVAC related 16
• Weighted impact 29%
Others
71%
HVAC related
29%
20. LEED
• Total credits/prerequisites 110
• HVAC-related 56
• Weighted impact
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Others
49%HVAC related
51%
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NIGHT
PRE-
COOLING Night pre-cooling is Circulation of cool air
within a building during the night time.
Hot dry environment is ideal for this technique,
however it should not be used in humid
environment.
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Air-to-Air
Heat
Recovery
Enthalpy
Wheels
A heat exchange enthalpy wheel, has a revolving
cylinder filled with an air-permeable medium with a large
internal surface area.
Heat transfer media may be selected to recover both
sensible & latent heat.
Because cross contamination can be detrimental, purge
section can be installed to reduce carryover.
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Air-to-Air
Heat
Recovery
Heat Pipe
System
A heat pipe heat exchanger is a
completely passive energy recovery
device. The tubes are divided into
evaporator & condenser sections by an
internal plate. Tubes are filled with a
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Air-to-Air
Heat
Recovery
Run-around
Coil
Typical coil energy recovery loop, places
finned tube coils in the supply and exhaust
systems. In re-heating of a Total Fresh air
system, two coils are placed in the fresh air
intake and after the cooling coil for re-
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Dedicated
Outdoor Air
Systems • A DOAS ensures Compliance with ASHRAE 62.1 for
proper multiple space ventilation and adequate IAQ
• Separate AHU to condition the outdoor air before
delivering it direct to the occupied space. This is most
beneficial in a facility with multiple spaces with differing
ventilation needs.
• This is not Treated fresh Air system which directly
connects to the return air mixing box.
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Demand
Control
Ventilation
using CO2
Demand control ventilation (DCV) is required for spaces larger than 500ft2
and with a design occupancy for ventilation of grater than 25 people per
1000ft2 of floor area and served by systems with one or more of the
following:
a. Air-side Economizer
b. Automatic modulating control of OA damper
c. Design outdoor air flow grater than 3000 CFM
CO2 sensor coupled to a controller operates the Volume control damper of
fresh air duct OR Operates the VFD of the fresh air fan.
Outdoor air flow rate for
ventilation is controlled via CO2
sensor and damper with a
modulating actuator. Applicable
to spaces that have wide
variances of occupancy such as
gymnasiums, auditoriums etc.
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Variable
Flow /
Variable
Speed
Pumping
Systems
Variable flow is produced in chilled water systems by using
automatic two position valves (2-way valves)
Variable speed pumping is achieved by using variable speed
drives on the CHW pump motor:
• Primary-only variable flow system with chiller bypass
line and a valve for minimum flow
• primary –secondary system, where secondary system
with variable speed pumps.
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Thermal
Energy
Storage for
Cooling
Thermal storage system (TES) utilize a building’s cooling
equipment to remove heat, usually at night, from and energy
storage medium (ice/chilled water) for later use as a source of
cooling.
Basic principle of TES is to reduce peak building cooling loads
by shifting a portion of peak cooling production to times when
the building cooling load is lower
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Desiccant
Cooling &
De-
humidificatio
n
Rotary desiccant dehumidifiers use solid
desiccants such as silica gel to attract water vapor
from the moist air.
Use in applications that require dew point at or
below 4 °C (40 ° F), such as film drying, manufacture
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Indirect
Evaporative
Cooling
Evaporative cooling of supply air can be used to reduce the
amount of energy consumed by mechanical cooling equipment
Direct evaporative cooling introduces water directly into supply
air stream, usually with a spray or wetted media.
Indirect evaporative cooling uses an additional water side coil to
lower supply air temperature and is piped to a cooling tower
where the evaporative process occur.