Hi HVAC Efficiency: 3 Part Series: Part 1: Innovations Offer Reductions In HVAC Energy Consumption But Are Often Ignored.

Hi HVAC Efficiency: 3 Part Series: Part 1: Innovations Offer Reductions In HVAC Energy Consumption But Are Often Ignored.

In recent years, the industry has devoted a great deal of effort to reducing the amount of energy used to operate buildings. During that time, a variety of innovative HVAC technologies and design strategies have been developed and proved in a wide range of projects. Those approaches, however, are often ignored when HVAC options are being weighed. That's unfortunate: Wider use of those HVAC strategies represents a substantial opportunity to cut energy consumption, since more than one third of the energy used in a building is for heating, cooling, and ventilation.

Those strategies are also crucial for projects aiming to achieve net-zero energy use. A net-zero energy (NZE) building is one where the total energy consumed over a period of one year, minus renewable energy generated on-site, is equal to or less than zero.

Designing a very efficient HVAC system, whether it's for a net-zero building or not, can be a significant task, and it is best accomplished through an integrated, holistic design approach. This approach requires the commitment and contribution of owners, architects, engineers, contractors, and other specialists. Building owners and facility managers play an integral part even beyond the design stage: Even the best-designed projects rely on the user's motivation to operate the building with a high level of energy efficiency — especially when striving for net-zero energy.

The appropriate selection of HVAC systems offers many opportunities to achieve great efficiency. But the first step in designing an efficient HVAC system, regardless of whether the project's goal is to achieve net-zero energy use, is to cut the demand for energy. This is accomplished by reducing building internal loads, by improving building envelope performance to reduce solar heat gains and conductive losses, and, at the same time, by maximizing the use of daylight.

Depending on the climate, cooling demand can be reduced by increasing building insulation and installing high-performance glass. Light-colored, reflective surfaces on roofs and walls and radiant barriers within ceilings are also important to avert solar radiation.

In recent years, there have been developments in dynamic building envelope technology that can alter performance in order to withstand peak periods. Smart glass or self-tinting products are controlled based on an electric signal. Phase-change materials can be installed in drywall in order to maintain surface temperatures during extended hot periods.

Internal electrical loads for lighting and power systems should also be reduced as much as possible to increase efficiency. About 39 percent of building energy use goes to lighting and office equipment. Reducing internal electrical loads also cuts the demand for cooling: For each kW consumed, a percentage of waste heat must be cooled.

PART 2: Consider These Passive Or 

Energy-Efficient Active HVAC Systems:

Once heat gain is reduced, passive HVAC systems or more energy-efficient active systems can be installed to satisfy occupant comfort.

Passive systems are effective in net-zero buildings because they allow the user to maintain comfort in a space without the need for energy. Common passive techniques include natural ventilation and the use of thermal mass.

Natural ventilation relies on outdoor air and appropriate high/low window placement to ventilate, bring in fresh air, and relieve hot air. Exposed thermal mass can often be provided in the form of concrete, water, or other materials to evenly regulate surface temperatures, even when exposed to heat. Exposed thermal mass is often used in conjunction with natural ventilation in order to pre-cool surfaces at night and store this coolth for daytime use.

Passive systems have two limitations: They can be slow to respond to changes in load, and they can have limited capacity. This makes the load-reduction strategies even more important. In mixed-mode buildings, passive systems are supplemented by active HVAC systems to operate during periods when outdoor temperatures are high or low.

Energy-Efficient Active Systems:

When it comes to active-system design strategies, it's important to remember that any measures that can help occupants maintain comfort without turning on building HVAC systems should be considered. Local personal workstation cooling systems or high-volume, low-velocity ceiling fans may allow facility staff to increase building temperature set-points while maintaining comfort. The premise of "adaptive comfort" is that people can accept a wider range of temperature if they have the means to make adaptive, local adjustments such as altering air velocity, modifying clothing levels, or changing the activity schedule.

For heating applications on small- to mid-sized commercial net-zero projects, electric heat pumps are often the preferred means for generating heat. The reason is that they can take advantage of electricity from on site renewable sources (e.g., from photovoltaics or wind turbines); that's why net-zero projects use natural gas heating systems less often than other types of projects. Other sources of heat, such as solar thermal collectors, are common ways to offset the electrical heating requirements.

Radiant systems, such as chilled or heated floors and ceilings, are effective for net-zero applications both in heating and cooling. These systems temper the environment without needing a fan to circulate air. Air-plus-water systems, such as active chilled beams, can also offset fan energy. A pump is required to circulate water; however, water is a much more efficient medium for transferring heat or cold than air.

For applications requiring large quantities of air, either due to ventilation or cooling demand, a means to offset fan energy should be considered.

The conventional method for doing this is to reduce supply air volume during temperate periods using a variable air volume (VAV) system. A VAV system uses a variable frequency drive in conjunction with the fan to modulate speed. Because fan power depends on airflow and static pressure, some systems look to save energy by reducing static pressure. An underfloor air distribution (UFAD) system can accomplish this goal by moving low-velocity air through a raised floor cavity to reduce the length of high-velocity air ducts. A UFAD system also supplies air at a higher temperature than VAV systems and often uses outside air to provide free cooling, leading to greater efficiency.

For larger applications, central plants employ water-cooled chillers with heat rejection from cooling towers. For this size of net-zero project, efficiency would be the driver for all mechanical components. There are opportunities, however, to use natural energy sources such as geothermal heating/cooling to modulate temperature in the HVAC fluids.

PART 3: Net-Zero Energy Buildings: Waste Heat Recovery And Renewable Energy:

Waste heat recovery and renewable energy are important strategies in net-zero energy buildings.

Because natural gas systems are less often used in net-zero buildings, there are fewer opportunities to recover energy from the heat-intensive processes. If natural gas is not used for heating, a project is unlikely to use fuel cells or micro-turbines, eliminating the ability to recover waste heat from those energy-generating systems.

On many projects, waste heat sources occur within the exhaust air streams or in condenser exhaust from heat pumps or chillers. Depending on the use of the incoming air and the quality of the outgoing air, heat can be transferred using air-to-air heat exchangers, air-handling-unit run-around coils, and thermal energy wheels. These systems either directly or indirectly transfer heat from one air stream to the next.

Another source of waste heat is the exhaust air from heat pumps or condenser water from chillers. If there is a simultaneous demand for heating (possibly in domestic hot water), this waste energy can be reused as a heat source.

Renewable Energy and Building Automation:

The steps outlined are important in another way for projects aiming to achieve net-zero energy use. Those projects decide which renewable power generation system (photovoltaic cells, building-integrated wind turbines, bio-fuel, or some other means) best matches the building demand and profile for the project type and region. Measures that reduce demand also help to reduce first cost of the generation system, and make it easier to deal with the source's intermittent power production. The protocol we've outlined makes it easier to size energy-generating systems at an appropriate and affordable capacity.

Building occupants also play an integral role in efforts to achieve energy efficiency, especially in net-zero buildings. If the user is unaware of the energy consumption in relation to the building energy generation, there is little chance of achieving a neutral energy balance (i.e., net-zero energy use) at the end of the measurement period. Building dashboards allow the user to monitor building energy consumption and to better understand when manual systems should be operated. For instance, the building dashboard may notify the user when outdoor air temperatures are acceptable for opening a window or inform the user when energy conservation may be needed on a cloudy day.

The design of a highly efficient HVAC system, especially for a net-zero project, is a complicated puzzle that requires all members of a project team to engage in the process. More than ever, there is reliance on all members to cooperate, motivate, and inspire their counterparts to achieve the common goal of energy neutrality. The reward is a net-zero building that can meet the needs of the present while having "zero" impact on the ability of future generations to meet their own needs.

Bruce McKinlay, PE, LEED AP, is a principal with Arup in Los Angeles and leads the firm's commercial property market in the Americas. He has collaborated on numerous sustainable projects where an integrated design approach has led to greater energy efficiency. He can be reached by email by clicking the following link here.

Jamey Lyzun, PE, LEED AP, is an associate at Arup and has 14 years of experience on projects. He has applied many of the techniques outlined in this article to assure that integrated strategies at the design phase can lead to low energy and sustainable outcomes during operation. He can be reached by email by clicking the following link here.

Hi Global Market for U.S. Indoor Air Quality to Reach $11.4 Billion by 2019!.

Hi Global Market for U.S. Indoor Air Quality to Reach $11.4 Billion by 2019!.

BCC Research reveals in its new report, U.S. Indoor Air Quality Market, the U.S. indoor air quality (IAQ) market is expected to grow to $11.4 billion by 2019, with a compound annual growth rate (CAGR) of 7 percent over the next five years. The equipment segment market is anticipated to grow at a CAGR of 7.4 percent.

Since 2012, continuing media attention focused on the health effects of toxic mold, the outbreak of infectious diseases (such as bird flu), and the increase in chronic respiratory diseases such as asthma have resulted in a new interest in IAQ in homes, commercial buildings, schools and hospitals.

There is a distinct equipment market within the industry that includes products such as air-cleaning equipment, HVAC equipment, HVAC replacement filters and IAQ instrumentation. This market, which was valued at $3.9 billion in 2013, is predicted to reach nearly $4.1 billion in 2014 and $5.8 billion in 2019, with a projected CAGR of 7.4 percent.

Although the commercial segment was the largest market for IAQ equipment and services in 2013, the residential sector is projected to move into the top position by 2019, with 29 percent of the market, followed by commercial buildings (28 percent), healthcare (16 percent) and schools (14 percent).

“The U.S. economy has continued to recover from the 2008–2009 recession, boosting the market for IAQ equipment and services,” says BCC Research environment analyst, Andrew McWilliams. “The IAQ market is important because health problems such as building-related illness and sick-building syndrome, as well as other ailments associated with poor IAQ in homes, offices and schools, are on the rise in the U.S.”

U.S. INDOOR AIR QUALITY MARKET determines the size of the overall IAQ market and its subcategories, such as IAQ equipment and technologies, consulting services and environmental services.

Hi' Tips to Improve Indoor Air Quality;

Hi' Tips to Improve Indoor Air Quality;

Indoor air pollution is considered as one of the top environmental risks to public health worldwide due to increasing number of building-related illnesses. 

Studies have found that concentration of indoor pollutants is significantly higher indoors than they are in outdoor environment, which is two to five times and sometimes hundred times higher than outdoor levels. 

As most of the people spend 80% to 90% of their lives indoor, indoor air quality has significant implication on sustainability.

Decreased indoor air quality can affect quality of life of the building occupant, increase health risks and increase the liability for building owner, decrease the productivity of occupants and reduce the resale value of the building. Poor indoor air quality can cause “sick building syndrome”, which is a medical condition linked to poor health and absenteeism.

Poor indoor air quality is due to many factors including but not limited to improper building design, inadequate ventilation, off-gassing of volatile organic compounds (VOCs) from furniture, carpets, paints and coatings, cleaning products, and from human respiration. Airborne particles such as lints, dust, dust mites, mold, bacteria, pollen and animal dander also contribute to poor indoor air quality. Indicators that are used to measure the indoor air quality include total particulate matter, total volatile organic compounds (TVOCs), formaldehyde, carbon dioxide (CO₂), carbon monoxide (CO), ozone (O₃), air temperature, relative humidity (RH). Concentration of CO₂ in the indoor environment indicates whether ventilation is sufficient or not.

In the Middle East region, most of the people live in enclosed air-conditioned indoor environments. With rapidly growing population, increase in number of vehicles on the road, high temperature level, ever increasing construction activities, regular sandstorm, concentration of air contaminants in the region is among the highest worldwide. Indoor environment also reflects outdoor air quality and pollution. Transport of outdoor contaminants to the indoor environment can result in occupant exposure to outdoor pollutants that have serious health impacts. In addition, there are many sources of indoor pollutants present in building materials, cleaning products, indoor mold and legionella growth, and emission from interior furnishings, finishing and equipments.

Tips to Improve Indoor Air Quality;

Indoor air quality is influenced by concentration of outdoor air pollutants as well as indoor source of pollution, characteristic of building and habits of occupants. Appropriate building design and mechanical system and control strategies as well as changing occupant behaviour can improve indoor air quality and health and comfort, performance and productivity of building occupants. There are a host of strategies to improve the indoor air quality.

Appropriate design;

Building envelop, orientation, and location of air intake, location of mechanical ventilation systems can contribute to indoor air quality. Hence, these factors should be considered during the design stage of projects to control the main source of pollutants for the whole building.

Whole house mechanical ventilation;

Properly designed and sized ventilation system can supply adequate outdoor air to indoor. In most of the green building rating systems, industry standards such as ASHRAE Standard 62 or Ventilation for Acceptable Indoor Air Quality are commonly followed.

Mixed mode ventilation:

Use of combination of mechanical and natural ventilation systems in buildings, such as automated window controlling systems and operable windows, can help in maintaining healthy indoor air quality.

Air quality management during construction:

During the construction phase, molds can develop due to exposure of building materials with moisture. Dust and particulates can easily accumulate on building materials if they are not protected. The air quality during the construction period can be protected by protecting the building materials from dust and particles and moistures.

High efficiency air filters: 

Filters prevent transports of outdoor VOCs, dusts, particulates and ozone indoors. Use of good particle filter such as high MERV rated filters in ventilation equipment are found to be the most effective filters in filtering outdoor dust and particulates out.

Maintenance schedule for HVAC filters:

Dirty filter can cause sensory irritation. Hence, appropriate maintenance schedule can prevent this to happen.

Use of low emitting materials: 

Use of materials that have low VOC content for products such as indoor carpets, rubber flooring, sub-floor materials, ceramics and ties, plasterboards, or other sealants and adhesives.  Also internal construction materials with low formaldehyde content can be helpful.

Conduct building flush out: 

Flushing out of indoor contaminants thoroughly in buildings before occupancy will help replacing dirty indoor air with fresh outdoor air.

Green cleaning program:

Select cleaning materials that are made of low emitting materials and employ a green cleaning program to reduce contaminant exposure.

Carbon dioxide monitors: Install CO₂ monitors in ventilation system and integrate them to regulate the supply of fresh air according to the building occupants demand. By doing so, if the CO₂ concentration increases beyond a set point, then the airflow automatically increases. 

Sustainable Cities.

Hi' Air Movement: A HVAC Moment: Winds of Change.

Hi' Air Movement: A HVAC Moment: Winds of Change.

The selection of appropriate equipment is essential to improving air movement.

The importance of air movement in the buildings of the GCC cannot be understated. It is debatable whether this region would have flourished as it has done in recent decades without it.

The provision of fresh and cool air to the structures in which we live, work and play has made the region a much more habitable place, especially in the scorching extremes of summer.

The existence of this fundamental MARKET demand has, of course, made the region a happy hunting ground for many local and global players in the MEP and HVAC industries,but the fecundity of the market has also increased competition, spurred innovation and changed the expectations of the air-conditioned masses. 

No longer will stepping in out of the heat to feel a cool breeze suffice. End-users now demand maximum comfort.

“Air movement can provide desirable cooling in ‘warm’ conditions, but it can also increase the risk of unacceptable cool draughts,” 

explains Hassan Sultan, director of mechanical department at MZ & Partners and former president of the ASHRAE Qatar Oryx Chapter.

“Noticeable air velocities can be perceived as providing freshness and pleasantness to the breathing air, but they may also be perceived as annoying. HVAC DESIGN innovations, energy conservation concerns, and new laboratory data on draughts have brought substantial attention to the issue of acceptable levels of air movement in the comfort standards.

“Air movement is one of the six main variables affecting human thermal comfort,” 

Sultan continues,

“which is the main goal of HVAC SYSTEM design and execution in buildings, especially in the Gulf region. The other five are air temperature, mean radiant temperature, relative humidity, metabolic rate and clothing insulation,” he adds.

With some of these variables obviously beyond the control of HVAC SYSTEM designers, their ability to harness air movement takes on even greater significance. 

The consequence of failing to achieve this can be a headache for an end-user, client/owner, and at least one member of the consultant-contractor team that delivered the system.

“Poor design and selection of air distribution terminals leads to draughts in some areas, stagnation in others, cold and hot spots and excessive noise – all these conditions have a bad effect on the well being and performance of the occupants,” 

explains Raef Hammoudeh, head of mechanical engineering for KEO’s design division in the UAE.

Looking at such problems in the GCC’s building stock, Hammoudeh says that part of the issue is to do with a misguided focus or lack of attention from mechanical engineers as to what is really important in HVAC SYSTEM design.

“In the majority of projects, design engineers and contractors tend to concentrate their efforts on the provision of the chillers, air handling units (AHUs), ductwork and so on, and very little time or design effort on ensuring that the air distribution systems within buildings are selected to provide optimum distribution within the spaces or to ensure the thermal well being of occupants,” he says.

fzal Basheer, senior mechanical engineer at Two Fold United Electrical and Mechanical Contracting, SHARES Hammoudeh’s dissatisfaction with the regional industry’s approach and believes that failures at the early design stages are often responsible for failure of installations themselves.

“[The potential for air movement problems] needs to be addressed before the actual installation of the system,” says Basheer.

“It is not only the building services systems, in terms of additional HVAC units or additional power requirements, that need to be addressed. If additional plant equipment is required, plant room or ceiling space must be available. 
If the equipment in the plant room needs to reach the required zone, slab openings or shafts must be available, which might not have been ACCOUNTED for at the design stage.”

Another piece of advice Basheer offers to system designers relates to the common air movement problem of odour circulation, which he says can be achieved by electrostatic precipitates and activated carbon AIR PURIFIERS.

“Consultants and clients need to make this mandatory by outlining it in the employer’s requirements and consultant design drawings,” says Basheer.

“What can be seen in several instances in the region is that if they have not been shown in the contract documents, the contractor doesn't install the odour management systems. Later on, if due to the foul smell the contractor is asked to come back to install the same, more often than not what is installed is more or less a quick fix due to spatial constraints and other design constraints that had not been ACCOUNTED for earlier.” 

A more fundamental criticism of those in the region responsible for designing its HVAC SYSTEMS and delivering optimum air movement comes from Khalid A. AlMulhim, Saudi Arabian ASHRAE Chapter officer and HVAC/utilities engineering consultant at Saudi Aramco.

“Designers are not aware of the latest ASHRAE and other industrial related standards,” he says. “They lack knowledge in the minimum requirements for different applications such as OFFICE buildings, hospitals, malls, laboratories, libraries, worship places, airports, computer centres, restaurants etc.

"They do not comply with minimum ASHRAE standard requirements in design, selection, installation and COMMISSIONING. This will lead to many technical issues, including but not limited to the system performance, commissioning, start up, maintenance and client satisfaction etc. If things are done right from the first step, everyone will save time and money.”

To address this gap in technical knowledge AlMulhim encourages the industry to push for widespread training to familiarise designers, as well as contractors and clients, with the latest industrial and international standards such as those of ASHRAE, the Air Movement and Control Association International (AMCA), the Associated Air Balance Council (AABC), the National Environmental Balancing Bureau (NEBB) and the SHEET METAL and Air Conditioning Contractors’ National Association.

Nevertheless, KEO’s Rammoudeh suggests that standards of HVAC design and installation are slowly improving, due in part, he says, to the efforts of some of the larger consultants and contractors to deliver HVAC SYSTEMS in accordance with recognised standards such as the Chartered Institution of Building Services Engineers (CIBSE), ASHRAE and Building Services Research and Information Association (BSRIA).

On a more local basis, he also cites the growing influence of Abu Dhabi’s Estidama sustainable design rating and the increased interest in Leadership in Energy and Environmental Design (LEED) in the UAE, both of which stipulate standards for internal air quality.

Notwithstanding the value of such standards to maximising the control of air movement, AlMulhim accepts that there may be a case for more bespoke regional ASHRAE standards given the distinctive climatic conditions experienced in the GCC.

“The ASHRAE standards related to air movement are largely sufficient for the Middle East environment,” he says. 

“However, special attention should be given during design to building infiltration, ventilation and AIR FILTRATION in order to overcome our harsh, hot, dusty and humid environment. So building infiltration, ventilation and filtration design standard requirements may need to be developed for our HVAC systems in the region. In addition, preventive maintenance programmes for HVAC systems are neglected in our region, where best practices and guidelines for these need to be developed as well.”

Two Fold Contracting’s Basheer is another advocate for more targeted regional HVAC standards, particularly for contractor’s handling of ducting.

“In the GCC, there is no stringent building codes for duct installations as there are no supervisory authorities like we have for power services and water services,” he says.

“Most GCC building codes fail to address air flow for comfort cooling. A duct system with terrible air flow can pass code inspection in several cities, and probably countries, as long as it is properly sealed and insulated. 
Too many contractors assume that as long as the JOB passes consultant or client inspection, it must be a good duct system. It is important to realise that when we depend on visual inspections to set the benchmark for good and bad, we are building to the lowest level allowed rather than the highest possible quality.”

Meanwhile, Hammoudeh also highlights regional contractors’ failure to take a more active role in ensuring that the HVAC systems being installed here are capable of providing good INDOOR AIR QUALITY. 

“They need to achieve this,” he suggests, “by making the correct sizing and selection of the entire air handling systems, installing the system in accordance with good standards that contribute to the proper cleaning, flushing, control, commissioning and adjustment.” 

Moreover, AlMulhim makes the point that contractors are perhaps given too much leeway by some consultants when it comes to procurement, deviating from specifications for costly but high-quality air system components and selecting 

“manufacturers that may not meet the industry codes, standards and certifications that have been specified in the construction documents”.

AlMulhim also raises the issue of contractor execution and delivery. “There is a lack of quality workmanship among some local contractors. 

They have a limited understanding of the importance of work quality on the site and complete the construction without implementing the standards that are defined in the construction documents as a minimum mandatory requirement to govern the installation of air movement and HVAC SYSTEMS,” he says.

If this delivery of design problem can be resolved, then it will be to the system designers themselves to push the industry forward in the quest for complete air movement control. 

KEO’s Hammoudeh says that at the upper end of modern HVAC DESIGN and the technology, there is no lack of fresh thinking being applied to the problem.

“New HVAC systems designs are using energy efficient, VARIABLE SPEED MOTOR technology for fans and pumps,” he explains.

“They use energy recovery HEAT EXCHANGERS between the supply and extract air streams, amd variable air volume (VAV) air distribution terminals to match the ventilation and cooling provided to each space with the requirements of that space. 

Supply and extract air volumes are adjusted in tandem to maintain the pressure regime in the zone using sophisticated automated controls.

Other COOLING SYSTEMS are also being introduced into the region such as underfloor cooling, radiant panel cooling and displacement ventilation. 

Furthermore, consultants are now are working more closely with manufacturers to ensure the equipment selections adhere to and compliment the design intent for the system.”

AlMulhim is slightly less enthusiastic about the work being done in regional HVAC design, particularly to advance thermal comfort in the Middle East, saying that thinking is often limited to VAV and VARIABLE FREQUENCY DRIVE (VRD) systems, as well as advanced temperature and pressure controls. However, he does highlight some “new innovation” taking place in induction low temperature air diffusers.

The importance of diffusers’ role in controlling air movement is something MZ & Partners’ Sultan also underlines. 

He encourages greater collaboration between the decision-makers in this area and a more considered approach before decisions are made.

“The design must include an adequate supply of ventilation air to the breathing zone of the space and a proper selection of diffusers,” says Sultan.

 “As the choice of diffusers is based on the mechanical engineers and architect, both the engineer and the architect need to work together to make the final selection.

In addition, the ideal selection is dependent on the type and operation of the air supply to the diffuser. Calculation of the air quantity required by the space and the proper diffuser selection, location, and design is one of the important issues concerning air movement.”

Finally, too often overlooked on too many projects, AlMulhim emphasises how a revised approach to COMMISSIONING could go a long way to addressing the region’s problems with air movement.

“COMMISSIONING is very important to minimise the potential for air movement problems,” he says.

“The COMMISSIONING process should start early from the design stage of the project, all the way to the start up and handover of the project. 

A certified commissioning expert should be involved during the design to verify each element of it and the latest standard requirements needed and to enforce and implement the requirements on the construction site.

“The commissioning process task should be stated in detail as part of the construction documents by the project consultant.
This will help the contractor to implement and complete the project while considering all the technical and standard requirements without any technical obstacles or performance difficulties during start up and operation of the HVAC SYSTEM.”

Given the long standing careless attitude to commissioning in the region, AlMulhim’s suggestion may be wishful thinking, but it is perhaps a point that needs repeating enough times by those of influence in the industry before clients, consultants and contractors across the region take it on board.

HVAC SYSTEMS designers and installers can be as good as they come, but if a system is not taken through a prolonged and detailed testing and commissioning programme, then all of that brilliant design and installation work may be for naught. 

The end result: uncomfortable, dissatisfied occupants airing their HVAC grievances to landlords and building owners, all putting a stain on the consultant and contractor’s name with each complaint.