Heat Recovery Ventilators (HRV)  (74)

Over the last decades heating, ventilation, and air-conditioning systems became significantly more energy efficient. This is immensely important as they are one of the largest energy-consuming loads in commercial and residential buildings. Smooth performance of the systems requires careful installation, thorough cleaning, and regular maintenance. Running an HVAC system (energy) efficiently is challenging because of constantly changing variables: people entering and leaving a building, changing temperatures and seasons which affect the heating, cooling, and air quality immensely. Research by the European Commission found that buildings are responsible for 40% of all European energy consumption. Emission reduction goals This has a significant environmental impact and will become more expensive over the next centuries while countries work on their net-zero and emission reduction goals. How can the HVAC industry, in cooperation with the green tech sector, ensure less energy consumption and fewer CO2 emissions? Are any other energy-saving options available? Energy-focused digital twins can be used for the planning, operation, and optimization of systems Following, three data-driven solutions for more energy efficiency in buildings are presented. To understand and operate a technical system it is necessary to have a precise understanding of the system’s parameters and boundaries. HVAC systems are installed in buildings. Buildings, although varying in size, purpose, and layout, can be described by a set of parameters called a digital twin. Energy-focused digital twins can be used for the planning, operation, and optimization of systems. Machine learning algorithms In HVAC applications, a digital twin can be used to design and operate equipment more precisely. It helps to detect defects quicker or even before a failure appears. This saves maintenance costs and reduces potential downtimes. The biggest potential of energy-focused digital twins might be the possibility to use those data sets to train machine learning algorithms. This allows the use of artificial intelligence to optimize HVAC systems. It can raise the energy efficiency of these systems and significantly reduce costs and CO2 emissions. Machine learning offers the HVAC industry immense possibilities. Tracking energy usage on building and room level generates a valuable data set that can be used to operate HVAC systems more energy efficient. Tracking room utilization AI can also consider the exact number of people present in the building when regulating the temperature One example of the use of AI to achieve more energy efficiency is temperature control in buildings. No matter what time of day or night, nor outside temperature or season, the AI algorithm can optimize the temperature in the building according to those variables. AI can also consider the exact number of people present in the building when regulating the temperature. This is important as the number of people and their body heat change the room temperature significantly. The system reacts to all variables by heating more or cooling down further. While it is possible to count people while entering and leaving a building, it is also possible to track their room utilization. The algorithm can not only notice the changing temperatures in rooms caused by body heat. Overall energy consumption It is also able to track where the lights are turned on and off and at what times. Possible reoccurring patterns in those actions can be identified by the algorithm. All this information can be considered when adapting building and room temperature. Tracking people’s actions gives AI detailed information to incorporate into the optimization processes to achieve more energy efficiency. In the same manner, air quality and humidity can be optimized. Especially in commercial buildings, the ventilation is often running too high Especially in commercial buildings, the ventilation is often running too high. Over ventilation is a large waste of energy. If fewer people are in the building it should be lowered to reduce the overall energy consumption. Especially in a work environment, both temperature and ventilation are of high importance, as it has a direct impact on the productivity of most people. Smart control system A smart control system will process all available data on the energy usage in a building and adjust the HVAC system accordingly, in real-time. The more information it can gather for a longer period, the better the system becomes. This saves energy, emits less CO2 and reduces costs. A manual adjustment will never be as efficient, as the number of variables is too large. Additionally, AI can identify any irregularities occurring in the HVAC system and alert the responsible person. Predictive maintenance ensures less downtime. Voltage optimization based on a building’s energy consumption data is a solution that can also enhance energy efficiency in buildings. It can be applied to reduce costs, electrical energy consumption and CO2 emissions. Optimizing the voltage level in real-time means reducing it to a lower level, based on the consumption of the building. Highest savings level The CE certification shows that fluctuations of voltage can be tolerated by a device Electrical energy is supplied to buildings by grid operators. They are supposed to supply 230 V. However, a constant voltage level cannot be guaranteed. The voltage fluctuates. Therefore, all electronic devices must be able to work within those fluctuations. They allow a range of plus and minus 10%, which is compulsory by law. The CE certification shows that fluctuations of voltage can be tolerated by a device. 10% of 230 V allows the reduction of the voltage level to a minimum level of 207 V. At this level, all devices in buildings are guaranteed to run smoothly. Every volt above 207 V can thus be considered more than necessary for the devices to work properly. This means, that at the highest savings level, all devices still work within their specifications. Lower electricity costs But with a lower voltage, the energy consumption is lower. Consuming less energy results in a reduced carbon footprint and lower electricity costs. The advancement of technology and availability of higher resolution data already allows building managers to look at optimizing HVAC systems for better energy efficiency, especially in newer buildings where those systems are installed right away. Consuming less energy results in a reduced carbon footprint and lower electricity costs This provides less energy consumption and less CO2 emissions. As buildings and their HVAC systems are consuming large amounts of energy which emits tons of CO2 every year, enhancing the energy efficiency in buildings becomes crucial on the way to net-zero. Energy-Saving solutions HVAC systems must work with the highest energy efficiency possible, considering that the weather extremes we are experiencing all over the world (colder winters and hotter summers) will increase the demand for them, if not make them indispensable. But these solutions are not only available for new buildings. Existing buildings can also be retrofit by their owners and operators to take advantage of the emerging data-driven trends in the green tech industry. Energy-saving solutions like voltage optimization can significantly reduce buildings’ carbon footprints. Combing several different data-driven energy-saving solutions will reduce the carbon emissions in the building sector significantly.

Most people spend about 90 percent of their time indoors. For home owners, indoor environmental quality (IEQ) is the most meaningful differentiator between ‘high-performance’ and ‘code-built’ homes. Indoor environmental quality  IEQ describes how well the indoor environment promotes occupant comfort and health. The components of IEQ include thermal comfort, indoor air quality (IAQ), sound and lighting. Requirements for optimal IEQ vary per occupant and household, due to individual health needs and levels of sensitivity to sound, light, color and temperature. Let’s discuss how to control the indoor environment for IEQ with particular attention to how heat pumps can help improve thermal comfort and IAQ. Start with the Building Envelope A healthy and comfortable home with optimal IEQ can be considered a single system A healthy and comfortable home with optimal IEQ can be considered a single system, which consists of interdependent parts and sub systems. Mechanical system designers give careful consideration to how components perform, in relation to each other and other variables. Code requirements for tighter building envelopes, improved windows, increased insulation values and more efficient appliances have reduced energy use intensity (EUI), since the 1970s, but also provide the foundation for better performing homes. Optimal IEQ requires control over how air, thermal energy (heat) and moisture enter, exit and flow through the building. Limit Thermal Bridging A thermal bridge is an area that has higher thermal conductivity than the surrounding materials, creating a path of least resistance for heat transfer. Thermal bridges reduce energy efficiency and create health and comfort challenges. When the components of a building assembly are made colder than the air in those spaces, there is the potential for condensation. This can reduce the durability of the building and create potential health hazards, such as mold. When designing high performance homes for maximum efficiency, health and comfort, choose techniques and products, like continuous exterior insulation and windows with low U-values, so as to eliminate limit thermal bridging. Heat Pumps and Thermal Comfort Comfort is a subjective experience, affected by variables, including the occupant’s age, level of physical activity and where they were raised. ASHRAE Standard 55 and the Predictive Mean Vote (PMV) concept use five factors to help builders design comfortable environments that are specific to occupants: Operative temperature Air speed Relative humidity Metabolic rate Occupant clothing High performance heat pump with variable speed compressor A high performance heat pump with a variable speed compressor can meet the challenge of subjective comfort, while improving the home’s energy efficiency. Heat pumps use the natural movement of thermal energy from hotter objects to colder objects, in order to heat or cool the home’s zones. In heating mode, the outdoor unit expands refrigerant gas to make it colder than the ambient air, enabling the unit to extract thermal energy from the outdoor air and transfer it via refrigerant lines to the indoor unit, conditioning the zone. Using this method, a heat pump can provide more energy for heating than it consumes in electricity. Even at low ambient temperatures, modern, all-electric heat pumps can be up to three times more efficient than conventional electrical-resistance systems. Heat pump systems with individually-controlled indoor units Heat pump systems with individually-controlled indoor units for each zone create opportunities to customize comfort, for specific occupants and activities (e.g., cooking, exercise, sleep). Using multiple independent units and compact duct runs offers more flexibility to design, according to occupant preferences. If the cost of changing ductwork in an existing house is prohibitive, ductless indoor units may be the solution. Performance can be improved by applying a heat pump system with a compact duct design Compact Duct Design for Heat Pumps Performance can be further improved by applying a heat pump system with a compact duct design, instead of a large, conventional duct design. During heating season, thermal energy is lost as conventional systems push conditioned air through long duct runs in unconditioned spaces. This heat loss through ducts can result in comfort issues and poor energy performance. In compact designs, duct runs are shorter and more centralized, with ducts running to interior walls and blowing toward exterior walls. With shorter duct runs and less opportunity for energy loss, contractors can install smaller indoor units with smaller and quieter fans that use less energy. Ductless indoor units for heat pump systems, such as recessed ceiling cassettes or wall mounts, don’t require ducts. Ducted air handlers and horizontal-ducted units are compact, making it easier to fit all the HVAC equipment and ductwork within the envelope. Indoor Air Quality Indoor Air Quality (IAQ) is particular to occupants, but less subjective than comfort Indoor Air Quality (IAQ) is particular to occupants, but less subjective than comfort. The primary objective of IAQ design is keeping pollutants from endangering occupant health. Contaminants of concern include particulate matter 2.5 (PM 2.5), acrolein, formaldehyde and volatile organic compounds (VOCs). PM 2.5, for example, can contribute to asthma, sinus congestion, coughing, skin rashes, brain plaque and cognitive issues, including headaches and sleep disturbances. Source control is the foundation of IAQ. In designing healthy homes, builders should avoid materials that off-gas formaldehyde and VOCs to limit the infiltration of pollutants. All-electric heat pumps align with the trend of limiting or eliminating the hazards of on-site fossil fuel combustion in healthy homes. After addressing source control, builders can apply methods and products for filtration, elimination and dilution. Whole-home Filtration The Minimum Efficiency Reporting Value (MERV) uses a scale of 1-20 to describe how effectively a filter can capture particles of a given size. A High Efficiency Particulate Air Filter (HEPA) with a MERV range of 17 to 20 and can remove 99.97% of airborne particles as small as 0.3 micrometers. When determining the level of filtration required, the impact of the static pressure drops associated with increases in the efficacy and depth of pleated filters considered. The duct design and Manual D calculations must account for pressure drops which cause air to move more slowly. Homes with multiple zones may have a mix of indoor unit styles, including ductless and ducted units. If a home owner requires higher filtration levels, HVAC contractors can install a complementary system purpose-built for whole-home filtration. High performance ventilation systems, ERVs and HRVs Healthy and comfortable homes use high performance ventilation systems to introduce fresh outdoor air. An energy recovery ventilator (ERV) or heat recovery ventilator (HRV) provides conditioned ventilation air to dilute pollutants and remove stale air, without significantly increasing heating or cooling loads. Humidity-balanced, conditioned fresh air may be directed to the air handler or ducted directly to zones served by ductless units. With modern construction methods, mechanical systems, knowledge of human physiology and help from immutable physical laws, HVAC contractors can help produce homes purpose-built for occupant comfort and health.

With ongoing efforts from governments across the globe to reduce carbon emissions and with an ever greater focus on sustainability, it is vital that the HVAC sector does its part in becoming more environmentally conscious. And, while there have been steps to become more sustainable, there is a huge amount that still needs to be done to make sure that many of the targets that have been set are attainable. In buildings, both large and small, industrial heating accounts for roughly two thirds of industrial energy demand and around a fifth of global energy consumption. Figures like this show the need to have efficient and environmentally-friendly HVAC equipment in place to make the crucial steps towards reducing the contributions these systems make to our carbon footprint. High energy consumption in construction sector A 2019 report by The International Environment Agency (IEA) showed that the buildings and construction sectors combined were responsible for over 30% of global energy consumption and nearly 40% of carbon emissions. This is indicative of the steps the sector needs to take to play its role in a more eco-friendly society, some of which are already underway. However, much more needs to be done if the UK is to reach its goal of reaching net zero carbon emissions by 2050. As we envisage what a post-COVID world might look like, businesses and governments are continuing to put sustainability and lower carbon emissions at the forefront of their planning and the HVAC sector is certainly no exception. But with change in the sector a daunting prospect, decision-makers often don’t know where to start. Smart Technology use in HVAC systems Smart HVAC uses sensors that integrate with a building’s automation system With the constant growth and greater deployment of smart technologies within the HVAC sector, this is certainly a way that systems can become more efficient. Smart HVAC uses sensors that integrate with a building’s automation system. These sensors then collect information about conditions throughout the building. Heat waves are now a far more common occurrence in the United Kingdom. The Met Office estimates they are up to 30 times more likely and will be a bi-annual occurrence by 2050. It is important that any uptake in HVAC usage doesn’t lead to a drastic increase in emission generation. This is one of the areas where smart systems will become crucial. Many scientists have been unequivocal in their sentiment that heat waves are a cause of greater emissions and expect temperature records in the UK and Europe to be broken more regularly, so sites will need to be equipped to handle these conditions. Regulating temperature with hand-held devices With wireless systems now much more commonplace, temperatures can be controlled easily from hand-held devices. With these new technologies, those managing the systems can also benefit from remote monitoring and maintenance, reducing the need to travel to the site for yet another environmental incentive. To accompany the smart systems, equipment including smart thermostats can be installed to maximize HVAC efficiency. Other smart systems available to businesses include smart furnaces and air conditioning units that are far easier to operate than their traditional counterparts. Reducing unnecessary ventilation While global temperatures continue to rise, air conditioning usage has increased and has contributed to greater levels of energy usage. A huge amount of needless emissions are generated by unnecessary ventilation, contributing heavily to heat loss and overall energy wastage. Recirculation of air is a traditionally lower energy cost method of retaining heat and keeping emissions low, however, we must be mindful of the risks associated with recirculating air. The risk of circulating diseases is negated somewhat with heat recovery ventilation, which both removes the risk of disease spreading and improves energy consumption. Efficiency performance of new AC units Air conditioning units in particular contribute significantly to a building’s energy consumption Air conditioning units in particular contribute significantly to a building’s energy consumption, equating to 10% of the UK’s electricity consumption and as such it is important that we bear in mind ways to counteract the emissions this creates. Global energy demand for air conditioning units is expected to triple by 2050, as temperatures continue to rise year on year. The efficiency performance of new air conditioning units will be the key, when it comes to ensuring that escalating demand does not equate to greater emissions. Another issue for suppliers and manufacturers to address is differing rates of consumption for AC units in different countries, with units sold in Japan and the EU typically more efficient than those found in China and the US. Modularization Modular HVACs have also become increasingly popular in recent years. Modular HVACs are responsible for heating, cooling and distributing air through an entire building, with their increase in popularity largely down to their greater levels of energy efficiency, cost effectiveness, flexibility and substantial ease of installation and maintenance. Modular HVACs can be tailored specifically for workspaces and they often allow work to be done on the systems without disturbing the workforce, achieved primarily through rooftop placement. Commercial workspaces are larger and often require differing needs to residential properties and can cater to a wide range of the specific requirements of work and commercial spaces. As we strive for lower carbon emissions, it seems that this trend will continue and will become a key area in reducing emissions that HVACs have traditionally generated. System maintenance and training To meet government and industry requirements, many new buildings will require HVAC systems that can be maintained simply in order to perform in a more energy efficient way. Many companies are looking at ways to become climate neutral and significantly reduce their footprint Many companies are looking at ways to become climate neutral and significantly reduce their footprint. Companies are following the likes of German-based company, Wilo Group, who have announced they are committing to sustainable manufacturing by developing a new carbon neutral plant and HQ in the next few years. Lowering carbon footprint As we continue to move towards an ever more environmentally conscious society, it will be of paramount importance for companies, governments and the public to think about ways in which we can lower carbon emissions. Smart technologies will certainly be at the forefront of this, negating many needless journeys and making it easier for industries to adjust settings and tackle issues remotely. Greater levels of training will help equip us with the tools to make sure we are best placed to reduce emissions and be more sustainable as a result. While the steps outlined above do show some progress and measures we can take, there is far more that we can do as a sector to significantly reduce HVAC’s carbon footprint and once we have moved beyond the impact of the COVID-19 pandemic, this will surely be at the front of industry leader minds.