Stanley De Vries is a team lead in application development in hydronics and HVAC systems at Danfoss.
Host Vic Marinich, global marketing director for air conditioning at Danfoss, is joined by Stanley De Vries of Danfoss to discuss heat pumps and the importance of hydronic balancing to ensure the building realizes full energy efficiency gains of a heat pump.
- Building HVAC systems have a primary loop, where the heating and cooling generation takes place, and a secondary loop, composed of the fans and air handling units that transfer the energy to the building. Both loops need to function efficiently to achieve the benefits of a more energy-efficient HVAC system.
- Hydronic balancing represents how the HVAC system distributes water through the building, in both full and part-load situations. The chillers, valves and air handling units need to be aligned. Designers and consulting engineers play a critical role in making sure the components work together properly.
- Traditionally, balancing was a manual process, with valves measured and set to a specific flow. Then automatic flow limiters were introduced. But neither manual nor autoflow work well in part-load conditions. The newer pressure independent control valves (PICV) make balancing easier and provide more precise control.
- In retrofits where a heat pump is installed to work in combination with the existing boiler, it is important to monitor the temperature of the water going into and coming out of the building. If the difference, or delta T, is small, that signals a balancing problem.
- Installing PICVs when installing a heat pump can future-proof the system by helping achieve proper balancing. Buffer tanks can also make the heat pump operation more stable.
- If an HVAC system with a heat pump is well-balanced, energy savings can be as high as 50%. PICVs are worth the investment to save both energy and potential repair costs, as balancing problems affect occupant comfort.
- Hydraulics matter. If the HVAC system is to work properly and realize the full energy efficiency gain from a heat pump, there can’t be shortcuts on the hydronic balance.
- In value engineering, the tendency is to choose the lowest-cost components. But it is important to think about the energy savings and total life cycle cost, not just the cost of the component. If you don’t install components that will allow your HVAC system to achieve hydronic balance, that will cost the customer more money in the long run.
To read how the Towson, MD courthouse used Danfoss components to install a synchronized hydronic loop, visit https://www.danfoss.com/en-us/service-and-support/case-stories/dhs/the-verdict-courthouse-retrofit-provides-comfort-efficiency-for-occupants-as-well-as-a-path-to-decarbonization/
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