Downtown Philadelphia’s Benjamin Franklin House needed an HVAC overhaul but, like most historic buildings, had no room to expand. EVAPCO reached into its archives for the specs of the building’s original cooling tower and created a more powerful, up-to-date version for the same space, making the installation process easier for Elliott-Lewis Corporation.

Upgrading ‘The Ben’ cooling system

Upgrading historic sites typically comes with challenges, such as limited space

The Benjamin Franklin Hotel—now known as The Franklin Residences or, simply, “The Ben”—was built in 1923. Upgrading historic sites typically comes with challenges, such as limited space. The building’s owners recognized that keeping tenants and guests comfortable during increasingly warm and humid summers would take the right systems and equipment working with minimal or no downtime.

A key component of The Ben’s cooling system is the cooling tower that serves a water-sourced heat pump loop in the building. For many years, this loop met most of the building’s cooling needs. Several suites still use packaged terminal air conditioner units, but many tenants have requested the switch to heat pumps. In addition, the retail space expanded from one floor to two. These changes have increased demand on the heat pump loop.

Installing new cooling tower

Mike McCauley, Sales Engineer at Elliott-Lewis Corporation, explained yet another reason for the demand increase. “Some equipment loses efficiency as it gets older. Back when it was built, the system was designed to meet certain demands. Well, those demands have changed. We have warmer summers now, and that’s taxing on older equipment. You can have the best maintenance in the world and the system still won’t be as efficient as it once was.

The increased demand did not come with increased floor space for a second cooling tower or even a new, larger one. The owners were faced with a challenge on how to get more cooling capacity using the same footprint. At the same time, the existing cooling tower, which had served the building since 1984, was reaching the end of its useful life.

New cooling solution

Our company maintains the cooling tower on this site,” said McCauley, adding “We realized that the equipment was at its end of life and told the owners that if they didn’t replace it soon, they’d be spending lots of money refurbishing it.

When the original cooling tower was built, it was not subject to certifications or ASHRAE 90.1 requirements, and building codes were different too. The building needed a new cooling tower that met current requirements—yet had the same footprint and a greater capacity. Engineers were called in to tackle the design, and Elliott-Lewis Corporation, which has served Philadelphia for a century, was chosen to install the new cooling solution.

Enhanced system cooling capacity

The original cooling tower was a discontinued EVAPCO unit, a PMTQ cooling tower

The original cooling tower was a discontinued EVAPCO unit, a PMTQ cooling tower. So, EVAPCO retrieved the design from their archives and built a new one to meet all the requirements for the project, including a sharply increased cooling demand, while maintaining the same footprint. EVAPCO’s solution increased the system’s cooling capacity on the heat pump loop from about 565 tons to 675 tons, without sacrificing space.

The original galvanized material was replaced by stainless steel, ensuring durability and a long lifespan. The addition of a custom fiber acoustic base for the tower ensured that the new unit was fully up to code.

Integrated with Super low sound fan

The new tower also needed to meet or exceed current codes for thermal and acoustic performance. The building sits in a densely populated part of Philadelphia, surrounded by office buildings and residences, so noise is a concern. The new unit features EVAPCO’s super low sound fan instead of the typical centrifugal fan that would be used with a forced draft system.

In addition, the unit has four fans drawing a total of 60 horsepower, up from the original unit’s 40 horsepower. Despite this increase, which achieves a greater capacity, the unit’s performance is more energy-efficient at part loads. Each fan is driven by a variable frequency drive (VFD) designed to run at part loads rather than cycling on and off when the demand changes. With VFDs, the unit can run all four fans at, for example, 30 percent, which is much more efficient than running one fan at 100 percent. The unit only uses the energy needed at any given load.

Modified heat exchanger

Replacing the old cooling tower with a modernized version allowed for minimal pipework

The heat exchanger, originally designed to meet the lower demand, would not serve the upgraded cooling tower to provide extra cooling to the building. Rather than replace the heat exchanger, the owners chose to modify the existing piece of equipment. Because there was enough room to add additional plates to increase capacity, the original heat exchanger was cleaned and expanded.

Replacing the old cooling tower with a modernized version allowed for minimal pipework, saving Elliot-Lewis time. “There were some piping changes,” said McCauley. “Old pipe was replaced because of its age, but other than that there was only some rerouting of pipes to accommodate the new tower dimensions.

Integration of VFD controllers 

Controlling the cooling tower required integration of the unit’s VFD controllers into the building management system. This step proved to be a challenge at first, but since its startup, the unit has been able to meet its required performance with no complaints from the owners. With its sturdy equipment and supportive professionals, The Ben is sure to maintain its reputation for luxury for many years to come.

Share with LinkedIn Share with Twitter Share with Facebook Share with Facebook
Download PDF version Download PDF version

In case you missed it

Lessons From The Past: The Value Of Ventilation In A Pandemic
Lessons From The Past: The Value Of Ventilation In A Pandemic

If history truly repeats itself, might we learn lessons from the past – even lessons about managing a novel coronavirus that upends our way of life and changes the world forever? The most commonly cited parallel to the COVID-19 pandemic is the Spanish flu pandemic of 1918. Both diseases are caused by viruses that had not been seen before. In both cases, no one had immunity to a highly infectious germ that was spread through respiratory droplets. Both outbreaks occurred in multiple waves over several years. Furthermore, in both cases, it became clear that ventilation, fresh air, open spaces and sunlight are useful factors in promoting good health. Fresh Air Movement During the time of the Spanish flu, there were signs posted in buses and throughout New York that advised: "Keep your bedroom windows open [to] prevent influenza, pneumonia [and] tuberculosis." There was even a national campaign known as the “Fresh Air Movement,” calling for people to be outside more, and urging greater ventilation indoors. The movement included a kind of traveling show that spread the word about the “national poison,” which was the result of people breathing stale air inside closed rooms. These concerns predated by decades our enthusiasm for “indoor air quality.” In became common after 1918 to position radiators providing steam heat under open windows to combine warmth with fresh air, even on the coldest of days.   The Open-Air Treatment of Pandemic Influenza It was also common practice by 1918 to place the sick outside in tents or in specially designed open wards But the advantages of fresh air go back even further, as described in a 2009 article in the American Journal of Public Health (AJPH) titled “The Open-Air Treatment of Pandemic Influenza.” During the 1918 pandemic, as today, many cities banned public assembly, closed schools, isolated those infected and mandated the wearing of face masks. It was also common practice by 1918 to place the sick outside in tents or in specially designed open wards, according to the AJPH article. The practice dates back to English physician John Coakley Lettsom (1744-1815), who was among the first advocates of the “open-air method.” The 1800s saw emergence of tuberculosis sanitoriums, which treated the lung disease with a combination of fresh air, gentle exercise in the open, nutrition, and a minimum of medicines. Lack of ventilation Spending time in well-ventilated houses in the country became seen as superior to patients being confined to warm, badly ventilated rooms to protect them from the supposedly harmful effects of cold air. Lack of ventilation forced patients to breathe foul air, contaminated with germs, over and over. Research later confirmed the importance of measures to prevent influenza virus from spreading through buildings. Improvements in air-handling equipment, portable filtration units, and introduction of physical barriers and other partitions or doors also provided protection. These lessons were clear long before the advent of the novel coronavirus that causes COVID-19. Their successful deployment during the pandemic have further supported their value. importance of HVAC Although the COVID-19 pandemic caught the world off-guard, there were plenty of historical precedents However, lockdowns during the pandemic have also tended to keep the population closed up in buildings, sometimes with less-than-adequate ventilation and access to fresh air. In retrospect, some of those decisions seem regrettable.  Although the COVID-19 pandemic caught the world off-guard, there were plenty of historical precedents. Copious research over the years supported the best approaches to stemming the spread of the virus, although it took time for historical insights to work their way into the general practice implemented in the current pandemic. There is also historical precedent for the importance of HVAC in the current pandemic. Ventilation and fresh air have become higher priorities, as has the HVAC market’s role in providing a safer indoor climate with minimal disease spread.

Pandemic Spotlights Need To Balance Costs While Improving Air Quality In Schools
Pandemic Spotlights Need To Balance Costs While Improving Air Quality In Schools

Attitudes about indoor air quality need to change, especially given the current pandemic that forces people to spend most of their time indoors. But addressing the pandemic through increased ventilation and better indoor air quality can be expensive. For example, the Los Angeles Unified School District, the second-largest in the nation, has spent $6 million on HVAC upgrades and new air filters in response to the pandemic and expects to pay about $1.7 million a month for ongoing inspections and filter replacements. Updating & Improving HVAC Systems Updating HVAC systems to minimize virus spread has been an expensive proposition all around. Some school districts in California report the costs are insurmountable. Sometimes seeking to replace or update an HVAC system opens a can of worms: Electrical systems must be rewired, asbestos must be removed, and/or an expensive roof needs to be replaced. Schools in low-income areas are especially likely to be in poor condition, and unable to afford improvements. Some school districts have used money from the federal CARES Act – a $2 trillion federal economic package passed in March – to make ventilation improvements. Hope remains that additional state and/or federal money will be available, but funding is still likely to be inadequate. Airborne Transmission Study showed that some classrooms had air change rates below 0.5 changes per hour The airborne transmission was initially underplayed as a means of spreading the novel coronavirus. There was more emphasis on the dangers of touch during the early days of the pandemic. However, the airborne (aerosol) spread is now believed to make up about 75% of transmissions. A group of 239 scientists from around the world advocated more action to address aerosol spread in a July 2020 open letter to the World Health Organization (WHO). The concern is a global challenge. For example, a survey of 20 classrooms in the United Kingdom, carried out by National Air Quality Testing Services (NAQTS), revealed very low air change rates that could increase the risk of virus transmission. The study showed that some classrooms had air change rates below 0.5 changes per hour (3 to 5 changes per hour would be desirable). Even small increases in flow rate could reduce the risk of infection significantly. Raising airflows from zero to 100 cu m/hour cuts the risk by up to a third, according to NAQTS. Fresh Air Ventilation & Filtration The Scientific Advisory Group for Emergencies (SAGE) advised the UK Government last fall of a need to ensure undisrupted education for children of all ages. A critical part of keeping children in school is clear guidance and support packages, including better ventilation and air filtration, particularly through winter. The German government advises schools to open their windows for at least five minutes every hour Other countries can learn a lot about the value of opening windows to allow in more fresh air from the Germans. For years, Germans have habitually opened their windows twice a day, even in winter. In fact, “lüften,” or airing a room, is among the cheapest and most effective ways of decreasing the spread of the coronavirus. The German government advises schools to open their windows for at least five minutes every hour; for example, when classes are changing. Improving Indoor Air Quality Airing of rooms is a likely factor in the lower number of coronavirus cases reported in Germany compared to, say, the United Kingdom. In the end, improving indoor air quality involves some combination of letting in more fresh air, upgrading air filtration systems, and installing technologies such as UV light to kill pathogens. However, implementing these measures only mitigates the likelihood of contracting COVID-19. Some risk remains.

What Technologies And Trends Will Define HVAC In 2021?
What Technologies And Trends Will Define HVAC In 2021?

The pandemic of 2020 presented unique challenges to the HVAC market, and in many instances, responding to those challenges relied on technical innovation. It’s safe to say that the pandemic accelerated several technology trends, redirected others, and overall raised the stakes in the industry’s ongoing challenge to meet customer needs across a wide spectrum. But what comes now? We asked our Expert Panel Roundtable to weigh in on this question: What technologies and trends will define the HVAC industry in 2021?

vfd