Revival of an older technology proves to be the right prescription for an aging hospital.

In 1892, the Sisters of St. Joseph founded a hospital, called St. Michael’s Hospital to care for the sick and the poor of Toronto’s inner city. Since that time, the hospital has preserved this commitment to compassion and excellence, while evolving into a center for innovation in patient care, as well as teaching and research in affiliation with the University of Toronto. In 2003, St. Michael’s carried that same commitment into saving money on its utility bill so those savings could be put into patient care. Another one of the hospital’s goals was to reduce its dependence on the existing steam source outside the hospital.

St. Michael’s Hospital is a rather old hospital with heavy demand. The hospital is currently connected to the district steam system. The hospital was looking for a way to decrease its steam demand by 30%. The cost of steam was $23 per 1,000 pounds of steam.

“Normally a facility will generate its own steam with boilers,” says Grant Markewitz, Ontario project manager for the Markham, ON–based Ecosystem, a company specializing in energy efficiency. “But in downtown Toronto there’s a company called Enwave, which has a steam distribution system throughout the downtown core. Many buildings in the city purchase their steam this way. However, the price of steam is directly related to the price of natural gas, which is what Enwave uses to fire their boilers. So when the price of natural gas goes up, the price of steam rises accordingly.”

Markewitz adds that steam is also very inefficient because of the distribution system: A steam network requires steam traps. As it travels around, steam tends to condense. That condensate is very hot and cannot be circulated; it must escape through the traps. Therefore, the steam is constantly condensing out and draining out of the system through the traps.

“All that energy is literally going down the drain and wasted,” says Markewitz. “In addition, because steam is extremely hot, it tends to be very difficult to insulate the piping properly so that radiant heat losses don’t occur from pipes distributing the steam around a building. By eliminating the steam network and switching over everything to the hot water that’s produced by a heat pump, you save a lot of energy.”

Enter Water-to-Water Heat Pump
In Quebec City, Rejean Cormier is a sales engineer with The Master Group, a wholesale York distributor for Eastern Canada and some areas of Ontario. Cormier felt he had the answer to the hospital’s equipment needs.

“I knew that York produced chillers with two compound compressors, one behind the other, for some desert locations, due to the high temperatures in those regions,” he says. “Ecosystem was searching for a thermal machine capable of giving them 130 to140 degrees Fahrenheit from their condenser and knew that these chillers were already designed for a desert climate. I suggested them for duty at St. Michaels.

“My part was to help them achieve the numbers they were trying to meet, and in the process I went back and forth from York to Ecosystem trying to get them the best of both worlds.

“From my point of view the challenge was to have a control panel to switch from heat pump to cooling and to make sure the unit is always alive, even though the load goes down,” Cormier continues. “This is truly amazing; York developed a state-of-the-art control panel specifically for this job but which will be used for future heat pump projects. Integrating its graphic display technology, York designed its panel to keep the heat pump running at all times in spite of load changes, using among other measures an automatic anti-surge system so the compressors operate safely and efficiently throughout its year-round operation. The control panel also manages the refrigerant and oil systems through several control valves and devices.”

This was a big project for the hospital. The equipment was purchased in 2004, installed in 2005, and running by 2006.

Ecosystem is mainly an energy-performance contractor with a focus on mechanical systems and turnkey projects, and a secondary focus on electrical systems. Its typical projects involve heat recovery, as well as alternative methods of producing domestic hot water and low-temperature hot water for heating purposes, such as efficient boilers and chillers, according to Michael Kern, Ecosystem vice president. Kern’s role has been to manage engineering, construction, and sales of energy systems.

“The reason why we chose the York/Johnson Control heat pump was its performance capabilities for the particular applications at St. Michael’s,” says Kern. “Our primary purpose in running this machinery is to generate low-temperature hot water. We rarely will send condenser water to the cooling tower; we utilize most—close to 98%—of the waste heat generated by this chiller to generate low-temperature heating water.”

Rebirth of an Older Technology
The idea for the York water-to-water heat pump was a technology often used back in the 1960s, according to Kern. That technology has faded over time. “We’re bringing it back because manufacturers such as York are updating the capabilities of their machines,” says Kern.

St Michael's Hospital is affiliated with the University of Toronto.

“We chose this particular piece of equipment primarily based on the heating and cooling demands of the hospital. Our feeling was that the York machinery had the best performance characteristics for the demand we were building. In other hospitals we have used equipment of other manufacturers, based on what their demands were.”

Along with a series of heat exchangers, the York machinery accomplished that goal, Kern reports. “To my knowledge, this is the biggest heat pump we’ve installed to date. We scour the universe for the best machinery for each project; that’s the job of our engineers. We don’t do the detailed engineering; we do the conceptual, and a big part of [the engineers’] jobs is to look for technologies.”

One alternative to using the York might have been to install a group of smaller machines in a series, according to Kern. “But, when you are dealing with an existing facility, you are also dealing with a limited amount of space in mechanical rooms, so I believe the York machinery was the only equipment that offered the tonnage that we required on this project.

“I believe this particular York machinery was the first such application in North America; I know it was the first in Canada. It typically is used in more arid regions internationally, and we had high expectations for it based on its performance characteristics. After the usual hiccups during commissioning, and now that everything’s been tested out and the components that caused problems replaced, this equipment is running the way we want it to.”

Putting Heat to Work in Water-to-Water Application
Because of its compound setup, which comprises two compressors and two motors, the York heat pump unit is distinctly nontraditional. It also has two stages—high and low—thereby producing the output of two chillers in one unit. Efficiency is increased, while the unit’s installation time, piping, and footprint are reduced.

“Because it’s not a single-stage centrifugal chiller but a dual-stage or two-stage compressor chiller, it is different than what we’re used to,” says Markewitz. “When you compress something it heats up, and when it evaporates it cools down. Therefore, if you take air and compress it, heat is produced.

“When refrigerant in an air conditioner gets compressed in the compressor, it gets hot; traveling to the evaporator on other side, it expands and gets cold. Air blows over the cold coils in your air conditioner, cooling the air in your house, while the fan or evaporator on the outside of your house blows air over the fan, actually heating up the air outside of your house. The air outside the house is hotter, while inside the air is cooler and that’s how your house is cooled.”

In the water-to-water application, there is a cooling tower on the compressor side (the hot side). Any excess heat gets transferred outside through a water-driven cooling tower. This is how the term water applies, according to Markewitz.

The cooling tower was already in place from the previous chiller installation. Two existing chillers were pulled out, and one single replacement with two small backups was installed in place of those chillers.

Instead of taking all the heat that would normally be wasted—that is, simply sent outside via the cooling tower and passed off into the atmosphere—the hospital now takes the heat and puts it to work for useful purposes.

These include heating the hot water dispensed through the tap or condensing (dehumidifying) the water from the air by cooling it down, something that must be done in the summertime as warmer air has the ability to hold more moisture than colder, wintertime air.

“Any humidity in the air we run through air handlers with chilled water coils. The air gets very cold; we bring it down to 50 to 55 degrees Fahrenheit, and the water condenses out and we come out with very cold air,” says Markewitz.

“This air cannot be sent directly into the patients’ rooms, so it must be reheated. These are called terminal reheats: heating done by the ‘hot’ side of the heat pump. Because the chiller or heat pump puts out cold and hot water, we are able to cool down the air with the cold water and heat it up again with hot water. Heat that normally would have been sent out by the cooling tower is used to reheat the air instead. Heat is therefore being recaptured as much as possible—everything recirculates.”

Additionally, law requires that a certain amount of air changes must take place per hour in order to maintain fresh air and proper air quality throughout the building. In previous building designs, outside air would be brought in; it would be conditioned, using energy to heat it up and humidify the air in the wintertime, or cool and dehumidify in summertime. When that air is used up, it’s sent outside.

“Air sent outside has already had energy put into it by heating it and humidifying it,” says Markewitz. “What we do is to recapture some of that heat and energy using this heat pump. So in the summertime ... we’re using mostly the chilled-water side and are recapturing some of the energy by reheating that cold air. In the wintertime we do just the opposite, heating up with the hot side of the chiller.

“It’s all the same installed equipment, all available all the time, but it does different things based on the time of the year, outside air temperatures, and what the different building needs are.” The older chiller equipment did not have that dual function.

The York chiller installation was a major project for the hospital. Inset: master group engineer Rejean Cormier.

Steam Heat Freedom
The new system has eliminated a significant amount of greenhouse gases that would have otherwise been produced, according to Markewitz. “They still have to use electricity, but we are using that a lot more efficiently. The main idea was twofold for the hospital. Number one was to save them a significant amount of money every year, along with reducing their greenhouse gas emissions. The other was to simplify their maintenance requirements because they no longer have to maintain the steam system or portions of it; this was a textbook case of a business decision that is good for everybody.”

Elimination of the steam humidification network also entailed Ecosystem’s installation of a high-pressure atomization humidification system in order to further reduce steam usage. Now the only steam used in the hospital is for backup and supplementary heating, and for specialty uses, such as in autoclaves sterilizing medical tools and equipment.

A Century-Old Medical Center and Its Challenges
According to Kern, the York heat pump is a fairly complex machine. “But my biggest challenge in this whole project has been client satisfaction,” says Kern. “The York did have hiccups and was down a lot at first, causing some operational difficulties, but many projects do have some rough spots at first, especially one as complex as this.

“Added to that was the fact that this was a very large old hospital, and all sorts of challenges were encountered along the way. This major facility is also a 550–bed acute care center serving the needs of downtown Toronto—it was complex to say the least.”

Working in a live hospital, Ecosystem had to be sure the operating rooms were available when scheduled. Patient areas and other hospital schedules also had to be carefully respected along with operational and maintenance schedules. They also had to work with individuals from both the United States and Canada in addition to the hospital; maintenance ended up being performed at some strange times.

“When it came to working with a piece of gear that everyone’s implementing for the first time, there was quite a learning curve involved,” says Kern.

Also, the hospital had been added on to numerous times, according to Markewitz. It had a number of different legacy systems. Some parts of the hospital are 100 years old, while others are six years old. Differing automation systems are in place throughout, and differing voltages in different parts of the hospital increased the demand on engineering.

“In some places we had legacy local controls, in others we had pneumatic controllers, and, in others, electrical controllers. We had to interface between them with the equipment,” says Markewitz. “We were presented with numerous obstacles.”

Now that the system is up and running, an additional challenge is that of monitoring the hospital’s savings. Because Ecosystem has a performance-based contract, it has invested heavily in monitoring technology. It has, for example, a relationship with a Toronto company called Dimax Controls, which provides technology for monitoring the hospital’s steam usage in real time.

“Steam-meter monitoring goes through a Web-based gateway,” says Markewitz. “We can log in, and I can look and see at any given time what their steam usage in pounds per hour may be. It is complicated, calculating the actual savings for the year. We have to establish a base year to compare against subsequent years. The most difficult part is that if there is any variance from what we expect, we have to go back and determine whether or not it’s due to our project or whether we succeeded far beyond our expectations.

“Because we have a performance-based contract, we have to make sure we are vigilant that both sides have a clear understanding of what’s going on in the hospital, the facility, and that we’ve fully explained how, when our equipment has gone online, they should expect to see savings. They in turn need to keep us fully informed of any maintenance work they’ve done that may be impacting their bills as well. The main difference between us and other companies is that we guarantee what we do, such as gaining a certain level of savings. We follow through during the whole life of our guarantee period. And that’s where open communication between Ecosystem and the hospital is crucial. We work hard to establish a long-term relationship with our clients.”

Plant Management a Breeze—Beyond Initial Hiccups
“Now I wish we had two of these heat pumps,” says Allan Kelly, manager of plant services for St. Michael’s Hospital. Kelly has worked for the hospital nearly six years. “We had our system up and running by the latter part of 2005. Before, we were running our heat pump as a chiller in the summertime and then as a heat pump in the winter; but now we’ve found through some design changes in the plant that it’s better for us to run it as a heat pump year-round. Since we’ve been doing this, we’ve really had good results.”

The hospital is still provided with chilled water, but the design parameters are constant now, allowing the facility to maintain its summertime baseload with this one machine, according to Kelly.

“We were also able to eliminate those pressure drops by fine-tuning the system,” says Kelly. “Now we don’t run as much steam as we had before, because before—in order to make reheat for the terminal units or radiation—we had to use steam by going through heat exchangers. Now we don’t have to use those, so there is less maintenance.”

So far the hospital has won two energy awards for its work in installing this equipment, one on the national level and the other on the provincial level. “These were awarded for the overall project and were great news for St. Michael’s Hospital,” says Kelly. “The national award was the CCHSE, awarded by the Canadian College of Healthcare Executives, who partnered with National Resources Canada. This was the last year this award was funded, due to changes in the government, so it was good to receive it while we still could.

“If some of the funding is taken away for energy conservation at the federal level, we may try to lobby for support again in Ottawa, but we’re still working on that,” says Kelly.

St. Michael’s also received the Ontario Hospital Association’s Green Health Care Award for hospitals participating in energy conservation from the province of Ontario. “Perhaps the project has inspired those working at the hospital to continue the good work beyond saving on their steam consumption and expenses,” Kelly says. “This was a win-win situation for the hospital: Not only did we save on our energy consumption, but we also eliminated chillers using R–11 refrigerant, which would have been banned in 2005 according to the Montreal protocol.”

Another plus for St. Michael’s was that Ecosystem was able to retrofit a lot of the system to run off the chilled water loop that the York heat pump produced, so a substantial amount of potable city water was saved from having to be used.

“Ecosystem’s niche is in heat pumps,” says Cormier. “They are a truly special consultant. They sell all sorts of measures for projects to owners to save money, and they get paid through the savings passed on to the owner.”

“Everything that a hospital does costs money,” says Markewitz. “This system definitely saves them money. Now they can take that saved money, place it into patient care, research, facility improvement, and all the other wonderful things that hospitals do and should be focusing on, rather than simply paying their utility bills.” 

Peter Hildebrandt is a writer specializing in science and engineering topics.

DE - January/February 2007