Visits to previous installations followed and Paxton were able to see, first hand, how expert design, considered specification and skilled installation combine to deliver outstanding cooling results.

Smart choice in Cooling

An important first step is the identification of hot or cold spots. Potential problem areas were considered. For example high storage areas, or the packing, loading and return bays. Also factors that can influence temperature such as doors and windows.

The Solution

Clean Air quickly got to work, scheduling the installation around the needs of Paxton to help minimise disturbance and avoid downtime in production.

For their economy, powerful cooling capability and strong green credentials the natural choice was the CoolBreeze QAD230 evaporative cooler. Four were duly installed, each unit able to reduce the temperature of 360 square metres by up to 16 degrees C. Hexagonal plenums were used to evenly distribute the chilled air to the factory floor of around 1000 square metres.

Finally to ensure that the newly introduced fresh and filtered cool air continually circulates the workplace, vents were strategically placed in the roof to expel the rising hot air. Commitment to health and safety was high. The factory has high ceilings and a double lift was required, not an issue for Clean Air engineers who have full ‘Working at Heights’ training.

The Result

The ultimate test came with the heatwave of July 2018 when temperatures regularly exceeded 30oC. The CoolBreeze units quickly proved their worth, keeping workers in air conditioned comfort with ease.

Perhaps not surprising given that they are designed and manufactured in Australia where such extreme high temperatures are the norm. Now that’s clever cooling!

Just two blocks from the White House, PNC Place is building a 12-story, 365,000 square foot office building, which will be their new Greater Washington regional headquarters. This will in fact be Washington D.C.’s first office building designed to achieve U.S. Green Building Council LEED (Leadership in Energy and Environmental Design) Platinum certification. The LEED Platinum certification reflects the highest level of environmentally sustainable building design recognized by the council. Opening in 2010, it will be a host to a number of office tenants and provide retail space, including a PNC Bank branch. This building features several solutions to reduce energy consumption, of which the most impressive is a 3-story “climate wall”, which is a wall of water to help naturally cool and condition the space. Having brought together natural elements and sustainable building design, the goal was to find an air distribution solution that would complement the application and fulfill the LEED requirements for energy-savings.

Challenges & Considerations

Working with local representative, DMR & Associates based out of Gaithersburg, MD and engineers at GHT, Limited, we found that they were challenged by the potential problems with delivering very cold air directly into a space, primarily due to condensation concerns, especially in critical areas such as the building entranceway, where building humidities are likely the highest. Previous designs had used series terminal units to mix some return air with cold primary air to raise the discharge temperature above the expected building dewpoint. This design has worked well, but is limited by the capacity of the fan in the unit, which must handle all the air being delivered to the space.

Product Solution

Several options were discussed. It was determined that the best option was a parallel, low profile unit with the backdraft damper removed (as it wouldn’t be needed) with a single DDC controlled ECM motor to often run at a reduced airflow (saving energy). The combined flow-rate of the primary and parallel fan could exceed that of a series unit, at lower unit fan energy, lower first-cost, and lower sound levels than any other option.

The End Result

Krueger is pleased to have had the opportunity to be involved with the engineers and designers of PNC Place to develop a product solution to fit such stringent energy requirements and help contribute to the LEED platinum certification. Scheduled to open in June of 2010, the true results of their planning have yet to be realized, but we are confident that the design and implementation of the 555 KLPP fan powered terminal units promote occupant comfort, lower first-costs, and capture energy savings.

Hvac design/build & retrofit solutions

To help this client meet its demanding commercial HVAC energy saving objectives, Mesa provided a high-performance HVAC design/build solution on a fast-track schedule. In addition to having maintained the client’s existing plant for many years, Mesa was chosen for this project because, as a HVAC design/build firm, the company offered more and better options than the single-source solutions proposed by two HVAC manufacturers.

More efficient cooling system, less space

Mesa’s HVAC retrofit solution involved replacing the hotel’s 350-ton industrial chiller plant with a more efficient 600-ton modular unit and performing a major electrical upgrade. In addition to accommodating the mechanical construction project’s fast-track delivery, the modular approach helped maintain the hotel’s historic character, minimized the central chiller plant’s footprint and allowed room for future needs.

The central plant was pre-built by the manufacturer, shipped in two sections and assembled on-site. The plant consisted of two centrifugal water-cooled chillers with factory-mounted variable-flow drives, and 2 two-cell stainless steel cooling towers with induced-draft, counterflow design, capable of cooling 2,000 gallons of water per minute. The plant also included chilled and condenser water pumps with variable speed drives, a cooling tower filtration and chemical feed system, a chilled water system expansion tank and air separator, two electric fan coil units for central plant air conditioning and a ventilation fan with gravity back-draft damper. A central plant industrial refrigerant monitoring system, a magnetic flow meter for monitoring the flow of main chilled water distribution and six automated isolation control valves completed the package.

Project delivery with no loose ends

In managing the project, Mesa made sure it took care of all the details. The company trenched new chilled water lines to an existing tunnel that led to the old chillers. It then installed new chilled water piping to — and within — the plant, as well as supply and return piping for the cooling towers. In addition, the company put in piping for chilled water, fan coil units and water treatment devices, and performed the various piping activities required to connect the chiller plant, the new cooling tower system and other equipment. The firm also installed a water source heat exchanger, which is part of the condenser loop. After completing the underground chilled and condenser water lines for the water source condensers, the company installed grade beams, structural pads and structural steel, so the towers could be set. The modular central chiller plant was then craned into place.

Cost-saving DDC system: BACnet

In addition, Mesa upgraded the plant’s existing direct digital control (DDC) system to the BACnet protocol, enabling it to better handle the new commercial cooling equipment. This protocol significantly reduced installation costs of labor, conduit and wire. Rather than pulling wire from all components back to the main controller, the company simply pulled the wire to the closest controller, from which BACnet can relay information throughout the system.

Hospitality facility background

The Mission Inn Hotel & Spa is a National Historic Landmark described by Will Rogers as “the most unique hotel in America.” Begun in 1876 as a boarding house, it now occupies an entire city block. Its multiple wings reflect architectural styles and furnishings ranging from the New World to the Far East. There are 239 guest rooms, including 28 suites, as well as 20,000 square feet of meeting and banquet space, a full-service spa and four restaurants.