Trends in HVAC Technology

By Neal Lorenzi of Health Facilities Management, interviewing Mike Patterson, Product Manager, Centrifugal Chillers, Trane

  1. What are the big issues for chillers in hospitals? What challenges do hospitals pose to chiller manufacturers?

The concept of “population health” is becoming increasingly common in healthcare. This is a more holistic, proactive approach to patient care, which the healthcare facility plays a vital role in. As a result, there is increasing pressure to make sure the right facility investments are made.

Hospitals have unique energy needs due to their around-the-clock operation and energy-intensive medical equipment, which puts a huge demand on chillers. Hospital owners and facility directors require chiller systems that not only help them meet demands and requirements related to temperature, humidity levels, infection control and providing a comfortable environment for patients and workers, but are also energy efficient and will help meet building performance goals and reduce costs.

Trane focuses not only on the individual chiller, but also on how the chiller will perform in the specified building application. While it’s important to choose chiller equipment that delivers high-efficiency performance, it’s even more critical to take into consideration all the systems within a hospital. This is important because installing a high-efficiency chiller alone may not yield the building performance hospitals are seeking to reduce energy costs. However, placing greater emphasis on total-system efficiency instead of chiller-only optimization helps ensure that all components of the system (not just the chiller) integrate for seamless operation and energy savings throughout the life of the system.

  1. What new chiller product have you recently introduced to the hospital market? What are its key features for improving efficiency?

Trane continuously seeks to enhance its product offering to provide the highest efficiency and most reliable chiller solutions in the market. Most recently, Trane has expanded its Series S™ CenTraVac™ chiller line with the new CVHM model to provide customers with a design solution focused on reducing the impact of greenhouse gas (GHG) emissions through reduced energy consumption and the use of low pressure, low GWP refrigerant. The new CVHM model operates with R-514A next generation refrigerant with ultra-low GWP of less than two.

In addition, the chiller’s industry leading efficiency is achieved through innovative AdaptiSpeed™ technology, the integration of an all-new specific speed, direct-drive compressor, a permanent magnet motor and the Adaptive Frequency™ drive. The Series S specific-speed compressor features the industry’s first mixed-flow impeller design. Offering the best attributes of both radial and axial designs, the impellers enable the compressor to deliver better efficiency across a wider operating range.

  1. Overall, how is technology changing for control of chillers in hospitals? 

The internet of things (IoT) has provided a new level of insight into the overall operation of heating ventilation and air-conditioning (HVAC) systems, enabling a greater level of efficiency and reliability. When working with customers, Trane takes a systems approach, focusing not only on the individual chiller, but also on how the chiller interacts with the other building system components. When a chiller is ‘connected,’ it broadens the realm of possibilities. The chiller can do something as simple as matching its operation to the building’s actual occupancy and load, or a more complicated optimization like switching energy sources.

Wireless technology offerings are increasingly vital options in hospital facilities given their flexibility and meeting building needs. Trane Air-fi™ wireless system operates on BACnet®, which is an open, standard communication protocol that provides the ability to integrate multiple HVAC systems and BAS together — allowing for more intelligent and effective hospital management.

Integrating information from multiple systems can help a hospital when it wants to track important key performance indicators in areas such as infection control, which can involve monitoring and keeping control of humidity levels and air changes for critical areas of the hospital. By continuously monitoring the chiller’s operating conditions and performance, facility managers can quickly react to changes any time − day or night − addressing potential problems before they become more serious.

  1. What is happening with refrigerants? With the phase-out of HCFCs, what is recommended for new equipment?

With the global increase in the use of refrigerants, regulations have continued to evolve, and Trane is ready to support customers through the phase-out of HCFCs and global phase-down of HFCs through the Kigali amendment to the Montreal Protocol. Trane provides customers with product choices that balance performance and sustainability without compromising safety, reliability and efficiency. In order to do this, Trane has expanded its chiller portfolio significantly in the last 18 months to address the increasing customer demand for climate-friendly systems. Our promise has always been to deliver the right refrigerant in the right product at the right time, ensuring that products achieve all regulatory requirements.

Ingersoll Rand created the EcoWise™ portfolio as part of the company’s Climate Commitment to reduce greenhouse gas emissions from its products and operations by 2030. Trane chiller products within the EcoWise portfolio meet the following requirements:

  • Are available with next-generation, lower-GWP refrigerants
  • Reduce greenhouse gas (GHG) emissions
  • Maintain safety and energy efficiency through innovative design
  • Meet or exceed emissions regulations

Trane offers water-cooled and air-cooled chillers within the EcoWise portfolio from 80 to 4000+ tons.

  1. What about sizing? For hospitals, is it best to use one large chiller or multiple smaller units?

There is no one-size-fits-all solution for a hospital. Due to redundancy requirements, it is extremely rare for any healthcare facility to use a single chiller. In healthcare, downtime is not an option and the ability for a chiller to come back online is critical – if one chiller fails, a standby unit needs to be ready to take on the total load. In addition, not having the right amount of chillers in the plant can negatively impact performance or result in capacity shortfalls.

In the past, many hospitals would install one small chiller to satisfy smaller night-time loads or for heat recovery. The February 2017 ASHRAE Journal article, “Using Low-Load Chillers to Improve System Efficiency,” states in its summary, “…using 2016 design practices, a system using a (same size) … chiller saves more energy than the ‘low-load chiller’ system, except in a climate that is hot and humid all of the time.”

Facility managers should focus on system efficiency by installing same size chillers with a variable speed drive on one of those chillers for use during low-load conditions.

A resource that is commonly used within the market is the 50% Advanced Energy Design Guide for Large Hospitals (50% Hospital AEDG). This design guide was co-developed by ASHRAE and several of its partners to promote building energy efficiency. It details multiple chilled water system features that will increase the energy efficiency of the building to include: chiller-tower optimization, low flow and high delta T designs, and heat recovery.

  1. What advances do you see in the future for hospital chillers?

With the continued focus for hospitals to conserve energy, save money, and build more sustainable operations, leveraging options that increase efficiency and lower environmental footprint will be key in creating systems for the future.

As chiller plants become more sophisticated in order to meet the complex hospital application requirements, so do the new chiller testing capabilities. With many advancements in the area, manufacturers can now offer factory testing under ‘real-world’ conditions that simulate operation of a specific project and application versus a standard Air Conditioning, Heating, and Refrigeration Institute (AHRI) test. The growing testing capabilities allow for documented proof of chiller performance and efficiency for the specific application before it leaves the factory, which more organizations will require in their quest to improve energy efficiency.

Additional chiller system advancements that are gaining momentum are heat recovery, free cooling and thermal energy storage. Chillers with heat recovery reduce the ancillary power necessary to reject the heat while also reducing the amount of purchased heat required. This reduces operating costs and lowers the emissions output through the reduction of burned fossil fuels, such as natural gas, that would otherwise be needed to generate heat.

Free cooling is a refrigerant migration feature that can provide up to 45 percent of the nominal chiller capacity, without running the compressor – reducing energy use and annual operating expenses for a hospital.

With a thermal energy storage system, the chiller makes ice during nighttime hours — when utility rates are usually at their lowest — which is then used to help cool buildings during peak-rate daytime hours. Ice-enhanced cooling systems not only use less expensive electricity, they also use less of it, in a more environmentally sustainable manner. In fact, ice storage systems are specifically identified by the U.S. Green Building Council as being eligible for LEED® design credits.

Trane, the Trane logo, CenTraVac, AdaptiSpeed, Adaptive Frequency, Air-Fi, EcoWise are trademarks of Trane in the United States and other countries.