With buildings responsible for 40% of global energy use and around 50% of city-wide emissions, Gareth Ash, Marketing Manager at Danfoss, considers the case for a ‘green restart’ for commercial building renovations.

Finding ways to make our commercial buildings more energy efficient is a critical step in the journey to a decarbonised future. If we are to achieve this ultimate goal then the buildings of the future, whether old or new, will need to be adapted or designed to be more climate-friendly, without compromising comfort for the occupants. With this objective in mind, we believe the retrofit building sector presents a mainly untapped opportunity to respond to the climate crisis and has massive potential for energy savings. As heating and cooling accounts for up to 80% of a building’s energy consumption, it makes sense to focus energy efficiency opportunities on this aspect of our existing buildings.

HVAC optimisation
It is widely recognised that to decarbonise our buildings requires a radical shift away from fossil fuels to sustainable solutions, such as district energy and heat pumps. However, this major step change is not without its challenges and although progress is being made it will take time. One of the most cost-effective measures to reduce energy demand right now is by optimising HVAC and technical building systems. On average HVAC optimisation can lead to energy savings of 30%, and with a short payback time of 2 – 4 years. Energy efficiency can be further increased with smart solutions such as demand-response, while digitalisation can be used to control heating and cooling as part of intelligent control systems that have access to accurate, real-time data. Furthermore, new technology can now assist in the design of building services that not only achieve optimum efficiency but also comply with Covid-19 safety requirements, including enhanced air filtration and multiple touchless features.

Digital revolution
Digitalisation has changed the way we live, work and interact, so it’s not surprising that this technology is now being applied to create efficient control of a buildings’ heating and/or cooling system. At Danfoss, we call the digitalisation of these systems HVAC 4.0 and are already engineering HVAC 4.0 for smart buildings with innovative products and services that make them more energy efficient, comfortable, and convenient for those who own them, occupy them, and maintain them.

Danfoss solutions to facilitate HVAC 4.0 include digital actuators that provide BMS with real-time HVAC data to enable Active Energy Management and digital valve control via fieldbus that offers advantages in remote commissioning, for example, as well as flow setting and flushing. There are also products for continuous logging of all system data to enable predictive maintenance and energy allocation, and automatically generated alarm messages to support fast and accurate troubleshooting. By using this new generation of connected solutions the energy efficiency and comfort of a building can be fully optimised.
Dynamic hydronic balance
The combination of Danfoss AB-QM pressure independent balancing and control valves (PICV) and our NovoCon S digital actuators is a good example of the increasing digitalisation in HVAC. Typically, terminal units such as fan coil units, chilled beams or radiant panels, provide heating and/or cooling in each room of a building. Depending on the size of the building this may require hundreds or even thousands of control valves and actuators for temperature control. Using the latest Danfoss digital actuators and PICVs provides the buildings’ BMS with real-time HVAC data, via BMS networks or Cloud-based solutions, while dynamic hydronic balancing ensures optimal energy efficiency, and comfort, throughout the building.
Perfect connection
At best, traditionally controlled actuators offer an analogue feedback signal to the BMS controller, while digital actuators offer many digital system parameters directly to the BMS via BACnet or Modbus. Danfoss NovoCon S digital gear actuators are designed to be directly connected to the BMS using BACnet or Modbus bus-communication. This adds a whole new dimension to HVAC control, offering designers, system integrators and building owners many features and benefits.
When Danfoss introduced NovoCon S almost five years ago it was a front-runner in establishing ‘Internet of Things’ solutions for smart buildings. As it is designed to fit AB-QM valves in sizes DN 10 up to DN 32 the nominal flow is limited to 4,000 l/h. However, as the concept of smart HVAC solutions has spread it has created new demand for accurate digital control of Air Handling Units, Chillers, and other high flow applications. To meet this demand Danfoss has recently expanded its NovoCon range with the NovoCon M, L and XL digital actuators for use with AB-QM. NovoCon M, for example, can be used in DN 40-100 valves for flows from 3-59 m3/h, while NovoCon L is for valves in DN 125-150 for flows from 36-190 m3/h. Completing the extended range is the new NovoCon XL which is used for valves in DN 200-250, making it suitable for flows from 80-370 m3/h.
The new NovoCon M, L and XL digital actuators can be daisy-chain wired using standard cables, making it easier to cover longer distances. The actuators are equipped with three resistance inputs to connect temperature sensors, for example. When such sensors are installed on the supply and return connections, the actuators can be used for advanced control functionalities like Delta T limitation or return temperature control. With these functionalities the energy efficiency of the AHU or Chiller can be optimised.
The NovoCon range is tailor-made to fit Danfoss AB-QM PICVs and establish the perfect connection between superior hydronic HVAC system performance and smart building automation solutions. The actuators can exchange accurate information about the actuator/valve position, settings, temperatures, and alarms, which gives system integrators and technical facility managers a unique insight, and remote access, to the HVAC system. The actual data supplied can be used to optimise system performance, improving the indoor climate and achieving an energy efficient building that delivers the highest comfort level at the lowest operating cost.
Greener future
All over the world, in light of Covid-19, we see a real opportunity for a green restart that will help us rebuild economies while, simultaneously, decarbonising them. Sustainable energy infrastructure and energy efficiency retrofitting of buildings are investments that can boost economic growth, while creating jobs and fighting climate change. In our view, changing how we heat and cool our existing buildings is a good starting point to a greener future. Making this transition will, of course, require close cooperation between many stakeholders but there will be benefits for all, including lower installation and running costs, optimum indoor comfort, superior HVAC system efficiency, and easier, more responsive servicing and maintenance powered by accurate, real-time HVAC data. For more information visit