Sota Construction Services new corporate headquarters is on track to achieve net zero energy status.

Sota Construction Services' corporate offices, located in Ross Township, PA, is a newly constructed 7,500 sq. ft. office building that exemplifies the most sustainable, state-of-the-art building technologies available. The corporate office facility, which opened its doors early 2010, is a registered USGBC, Leadership in Energy and Environmental Design, New Construction Project (LEED® NC). It’s anticipated to achieve a LEED Platinum rating, and could rank as one of the first Platinum LEED NC buildings in Pittsburgh.

Sota Construction Services' new state-of- the-art green corporate office embodies the company's core principles and philosophies towards responsible planning and sustainable construction. Their green portfolio includes many, if not most of all current leading edge technologies. Tudi Mechanical Systems, Inc. has enjoyed the privilege of partnering with Sota Construction Services on many new construction, renovation and energy projects. It has been through the integrated design process that Tudi Mechanical company has been able to collaborate with many of their green projects, thus incorporating many renewable technologies such as solar, geothermal, micro-turbines and net-zero energy.

Calling All Experts
Owner Ernie Sota assembled his "green dream team," to include internationally acclaimed engineering firm, ARUP and leading international building scientist, John Straube, Ph.D., as well as regional favorites, Gerard Damiani of Studio d’ARC, project architect and Jonathan Iams of Iams Consulting, project engineer. As part of Sota's integrated design approach, Tudi Mechanical Systems, Inc. collaborated during many design meetings, exchanging technology ideas on related application solutions.

Key advanced technology building components encompass the ultra high efficient thermal envelope, natural building materials with thermal mass and hygric features, biophillic space, air-to-air energy recovery, radiant slab cooling and heating and closed loop geothermal with "free energy" economizer cycle. Also taken into account for the low energy design are day lighting, occupancy sensors, natural ventilation and energy monitoring for benchmarking measurement and verification protocol.

Because of the critical dew point control required for radiant cooling, much related attention was focused accordingly. Key radiant cooling technology resources were utilized for additional design collaboration. Tudi Mechanical helped source two other reknown radiant leaders, Dr. Stanely Mumma, Ph.D., PSU, and Geoff McDonnell, P.E., radiant cooling systems author and engineer.

The additional collaboration allowed further finetuning of the complex designed radiant systems by incorporating enhanced tubing spacing, expanded radiant zoning, as well as optimized dedicated outside air system. Typically, radiant hydronic heating of high thermal mass slabs incorporates tube spacing at 12-in. increments with circuit lengths varying 200-ft. to 500-ft. Twenty five years of western European research and application of radiant cooling has demonstrated that closer tube spacing,— for example, 6-in. to 9-in. is more suited to deliver the maximum BTU's per /sq.ft. of radiant cooling. Therefore 8-in. tube spacing was selected for the high thermal mass floor slab systems. Along with tube spacing adjustments, additional zones were considered for solar tempered north and south zones on both the 1st and 2nd floor offices.

Earth plaster and straw were used as a hygroscopic component in the wall structures.

With regard to the outside air ventilation system, conventional wisdom holds that building pressurization is used to control humidity when primary cooling systems are sensible load based. According to research by Dr. Stanely Mumma of Penn State, calculated internal latent loads are used to determine the dryness and volume of related Dedicated Outside Air Systems, such that the total outside air capacity results in scheduled outside air volumes equal to or less than typical office ventilation requirements. Therefore, the DOAS air flow and latent capacity selection was optimized with a standard unitary two-speed heat pump coupled with dual sensible/latent flat plate air-to-air energy recovery technologies. Finally,— and more unique with this building system, than other radiant cooling systems, —was that the natural building materials incorporated a hygroscopic component in the earth plaster and straw bale wall structures, which also serves to augment the latent load control. Monitoring results of the first cooling season proved humidity control a success with humidity levels never exceeding 56%.

Total Quality
Another key challenge, was the application and programming of DDC automatic control system. Key features included, were the slab temperature monitoring, dew point control sensors, free cooling geothermal economizer control, air to air energy recovery ventilation control and the "red light – green light" natural ventilation monitoring system. The continuous commissioning process employed, allows for ongoing refinement control sequences, algorithims and set points as well as hydronic loop and DOAS reset temperatures. The DDC system is equipped with a web based computer system that allows the owner and mechanical contractor to continuously monitor and adjust control points from any Internet connected computer. The graphical interface offers real time HVAC monitoring as well as power consumption data for the building lighting loads, plug loads and HVAC loads. The major geothermal heat pump equipment included the manufacturer's open Lon based DDC communication protocol, that seamlessly integrates to the all encompassing Honeywell building automation system.