Air conditioning professionals attending this year's AHR Expo had the opportunity to preview Danfoss' extensive portfolio of rooftop components that unite to help OEMs tackle seasonal efficiency and refrigerant changes—including innovations like the Interlaced Micro Channel Heat Exchanger (iMCHE).
Designers of rooftop units are facing a pair of environmental challenges: the US Department of Energy's 2023 energy efficiency standards requirement of a 15% increase in integrated energy efficiency ratio (IEER), and the introduction of regulations by a growing number of states to replace HFC refrigerants like R-410A with lower-GWP alternatives.
Part-Load Efficiency And Switch Refrigerants
At AHR Expo 2020, Danfoss showcased a substantial portfolio of components that solve these challenges by helping manufacturers improve part-load efficiency and switch refrigerants, often with minimal redesign costs, and shared with visitors the system-level benefits revealed in laboratory tests.
Danfoss iMCHE enables several circuits to share the heat transfer area in a single coil
Several of the innovations and solutions combine to give OEMs an immediate boost in part-load efficiency. Some of the components can achieve savings of more than 15% on their own, helping OEMs meet the more stringent 2023 IEER regulations.
Heat-Transfer Efficiency
The Danfoss iMCHE enables several circuits to share the heat transfer area in a single coil, improving part-load efficiency by more than 20%, maximizing heat-transfer efficiency, and reducing refrigerant charge in a compact shape which minimizes weight.
The third-generation VZH variable-speed inverter scroll has a higher part-load performance and wider operating map than ever before. The scrolls range from 4 to 26 TR, which can be further expanded to 52 TR in a hybrid tandem, and, like all Danfoss inverter scrolls, now include Intermediate Discharge Valve (IDV) technology for maximum part-load efficiency.
Compressor Control Logic
The powerful new MCX15B2 and MCX20B2 controllers are ideal for use in rooftop units. As enhanced versions of the popular MCX-B-series units, they offer best-in-class connectivity and safety, along with new compressor control logic for industry-leading Danfoss VZH inverter scrolls, enabling system designers to get the biggest possible benefit from variable-speed compression in any conditions.
Danfoss manifolds are designed to minimize OEMs’ system losses, and are assembled in Danfoss facilities
Pre-assembled tandem and trio manifolds enable OEMs to improve their system’s seasonal efficiency while reducing complexity in the supply chain and manufacturing processes. Danfoss manifolds are designed to minimize OEMs’ system losses, and are assembled in Danfoss facilities using the highest quality manufacturing techniques to ensure reliability.
They include multiple combinations in even and uneven tandems and trios, and hybrid tandem configurations—and all feature patented Organ Pipe technology for optimized oil management under part-load conditions.
Multi-Refrigerant DSH Scrolls
With more than half the US population living in a state included in the United States Climate Alliance, many manufacturers are working on two or more rooftop configurations in parallel—one using R-410A, and one using refrigerants with a GWP rating of 750 or less, such as R-452B, R-454B, or R-32. As there is no single, clear R-410A replacement, visitors to AHR Expo 2020 were able to discuss with Danfoss experts the ways to maximize refrigerant flexibility.
Multi-refrigerant DSH scrolls are qualified for use with refrigerants R-454B, R-452B, R-410A, enabling multi-refrigerant drop-in support while minimizing inventory and redesign requirements. Like Danfoss VZH scrolls, they include IDV technology to improve IEER.
Danfoss Colibri® Electric Expansion Valves
DSH scrolls are just one part of Danfoss' extensive range of multi-refrigerant components qualified for use with low-GWP A2L refrigerants. For example, Danfoss Colibri® electric expansion valves are qualified for use with more than 30 refrigerants—including R-410A, R-32, R-452B, R-454B, and R-1234yf.
This flexibility enables manufacturers to benefit from precise liquid injection in a light, easy-to-install format, without a need to redesign their system for each refrigerant. ETS Colibri will also benefit from its own power back module, the EKE2U, to be released later in 2020, to enhance system reliability in case of unplanned system shutdowns.
Victor Marinich, Global Marketing Director—Air Conditioning at Danfoss, said: "The need to protect our environment means rooftop manufacturers are responding to a fast-moving regulatory landscape.The best part is, these components all work together perfectly. That means you can use them to create a big, cumulative impact on part-load efficiency, while also maximizing reliability."
