How to design high performance HVAC system for a sustainable environment?
HVAC (Heating, ventilating and air conditioning) systems had recorded the highest energy consumer in the UK, reaching almost 50% of the total energy consumption of the country. Consequently, significant savings in money and energy can be done by designing energy-efficient buildings from the early stages. In fact, the use of high-performance HVAC systems can result in cost savings ranging from 10%–40%.
The term HVAC refers to heating, ventilating and air conditioning. It describes a conglomeration of different systems that work together to design an environmentally friendly living space.. Firstly, heating can be done by heating the air in the space through either hot air sources or radiant sources. Secondly, ventilating is done through natural air ventilation or through mechanical odour controller and air distributers. Lastly, air conditioning which is controlling the air temperature and humidity in the space that is mostly done by air-cooling or water-cooling systems.
HVAC is considered one of the main factors affecting the carbon emission- at this point, we are not talking about more financial savings anymore. Instead, we are highlighting the problems we are facing such as ozone layer depletion, global warming and climate change.
We are actually running out of time because in 2018 the Intergovernmental Panel on Climate Change (IPCC) reported that to keep the rise in global temperature below 1.5C (the safe limit) CO2 emissions should be cut by 45% by 2030. . Prince Charles has pointed out to this problem in the last reception for Commonwealth foreign ministers “I am firmly of the view that the next 18 months will decide our ability to keep climate change to survivable levels and to restore nature to the equilibrium we need for our survival”.
In this article, we will show you the most used HVAC systems in construction projects and how to design a high-performance building step by step!
HVAC system types
An HVAC system is the main artificial method to provide thermal comfort for users inside the space. It can be classified into central, partial or local systems, and each system of them include heating system, ventilating system and air conditioning system. Here are the most used systems types in each category according to the whole building design guide:
- Boilers: they depend on generating heat from water steam and usually fuelled by natural gas, fuel or coal.
- Furnaces: there are two types of furnaces, fuel, and electrical ones. They are used more in residential spaces and it depends on heating coilers to produce heat.
- Heat pumps: these are devices that extract heat from cooling systems as refrigerators or air conditioners by reversing the cycle, bringing the hot air from outside to the destination space inside again.
- Constant air volume (CAV): systems that deliver a constant rate of air while varying the temperature of the air supply.
- Variable air volume (VAV): systems vary the amount of air supplied to space while holding the supply air temperature constant.
- Low-flow air diffusers: active and passive air diffusers that supply air in low flow.
- Fan-powered VAV: terminal units that provide another method to improve air distribution at low load conditions.
- Raised floor air distribution: a method of delivering air through a series of adjustable floor-mounted permits room air to be stratified with lower temperatures in the bottom part of the room where people are located and high temperatures towards the ceiling.
Air Conditioning system
- Chillers: the devices that are used in large complex buildings to produce cool water, this water is then pumped to air handling units to cool the air inside.
- Condensers: they are heat exchangers needed for the chillers to resist the heat that has been removed from conditioned areas and direct this heat into the ground or river water. They basically have two types, air-cooled and water-cooled condensers, however, air-cooled condensers are less costly than the air one.
After knowing how important it is, and what its main systems are, here are our recommendations to design a highly efficient HVAC system in a building.
10 steps to design high-performance HVAC buildings
Designing a high-performance building is not a result of HVAC system efficiency only. They are multiple aspects that should be taken into consideration from the beginning, where it is a thing that can be addressed as a design approach on its own. Starting from the orientation of the building, building materials, skin and energy consumption. However, here are our recommendations to produce a suitable and considerable HVAC system for a building.
- Set your design goal at the early stages of the building.
- Design according to the code requirements of the existing building location.
- Coordinate between the HVAC, lightning and electrical systems to get the utmost output of the energy savings.
- Calculate the actual load of the building several times and under different constrains to ensure getting an accurate number.
- Design energy management system that can shed unnecessary load at different times of the day ex. night times.
- Plan for future expansion. It’s important to design a flexible building that can incorporate any kind of future expansion but don’t size its loads at the initial phase of the project.
- Establish a quantitative goal for yearly energy consumption of the building.
- Consider using new developed tools and equipment that save energy especially in large commercial facilities.
- Ensure direct communication and coordination between all the project parties using a defect tracking software as PlanRadar to minimize the negative impacts of regular construction defects.
- Apply a quality maintenance program that should follow up with the project after its delivery.
It’s time to take action. Big building and construction firms started shifting their normal design approaches into more sustainable, greener, climate change friendly facilities. Be part of the change now and lead the future transformation in your company.