Manufacturers' perspective on mixed-use buildings
Two manufacturers provide insights about engineering electrical and mechanical systems into mixed-use buildings.
John Bailey, Senior vice president of sales, ClimateMaster Inc., Oklahoma City
Jim Kukla, Product manager, sanitary systems, Kohler Power Systems, Sheboygan, Wis.
CSE: What solutions do you provide engineers for mixed-use building projects?
ClimateMaster: We have a broad range of product configurations and sizes from 6 to 70 tons. This allows our heating and cooling products to fit in various spaces and be easily configured for any application. But probably the chief advantage of water source products is that they move energy. Due to varying loads of a mixed-use building, often heat can be pulled from one area (example: commercial laundry room/fitness center/building core) and be used in another area (example: perimeter space heating). This is a tremendous way to save energy and be extremely efficient.
Kohler Power Systems: We provide gas and diesel generator sets from 10 to 3,250 kW, automatic transfer switches (ATS), and paralleling switchgear, providing totally integrated solutions to ensure fully coordinated systems with a single point of responsibility. If the owner of the building is leasing to mixed tenants and has an on-site power system—depending on codes—ATSs or paralleling switchgear could be used to segregate electrical loads by each tenant. The owner could also use the same type of system to supply tenants who would pay a premium for backup power.
CSE: Please describe a recent mixed-use building project you’ve provided assistance on—share challenges you encountered, how you solved them, and aspects you’re especially proud of.
ClimateMaster: Probably the most intriguing was a building done with large lower-level retail spaces. When doing the load and energy profile no one imagined these retail spaces would leave all the doors open in the summer. This added dramatically to the cooling load. To complicate matters it was a ground source job and the ground loop could not keep up with the load. To correct this issue, the location had enough land to install a fountain which really acted like a cooling tower, making this a hybrid application. In addition we cycled the pumps on at night to just cool off the loop. The problem was solved.
CSE: What factors do you need to take into account regarding building automation systems (BAS) or building management systems (BMS)?
Kohler: It is important to ensure your on-site power system is capable of interfacing with building management systems. It is also important to understand who wants and/or needs to monitor the power system (i.e. the tenant, building maintenance personnel, etc.). Some of the things to consider is what information to retrieve from the system, the communication protocols of the building management system (BMS), what type of converters may be needed (i.e., modbus to Ethernet), and the interface to the network. Kohler Power Systems has controllers on the equipment capable of interfacing with BMSs that provide seamless integration of the emergency system into the BMS.
ClimateMaster: Our company makes this simpler than other manufacturers. Because we are open to all protocols, we are not pushing our “front-end software” like many others. We simply offer an open protocol controller on our equipment that is easily connected to the BMS which was chosen by the owner.
CSE: What types of tools do you recommend for mixed-use building projects? What should be in every engineer’s “toolbox”?
ClimateMaster: A good load-sizing program is a must. Regardless of what equipment is being used, without an accurate load profile adequate comfort in cooling and heating is a gamble. Many times units are oversized to handle the unknown at the expense of operating efficiency and project first cost. This causes dehumidification and short run time issues. Likewise, under-sizing units will lead to occupant complaints and other issues from the lack of properly sized equipment. In a mixed-use building, this is exaggerated due to different parts of the building having different load profiles. For instance, a kitchen or laundry room will require greater cooling and outside air requirements than an office space; combining the two applications necessitates attention to the unique requirements of each space. So a good building load and profile is a must.
CSE: What’s the one factor most commonly overlooked when working on mixed-use building electrical system projects?
Kohler: For an on-site power system, load requirements and the segregation of these loads by each tenant need to be considered. Also, balancing the load by phase on the power system is an important consideration.
ClimateMaster: There is really nothing that sticks out as being most common. ClimateMaster makes it so easy to integrate by the varied sizes and voltages available that normally there are no electrical issues.
CSE: What unique requirements do HVAC systems have, and what questions/issues have you helped resolve?
ClimateMaster: Many times existing buildings are being repurposed and converted into mixed-use buildings. This may present a challenge when upgrading the HVAC system. ClimateMaster has developed products specifically for retrofit applications where a small footprint may be more important than efficiency. We have worked to achieve highly efficient multi-stage products with a compact footprint for areas where loads vary depending on time and use. The reason water source is widely prevalent in mixed-use building is efficiency versus cost. They are by far the easiest HVAC system to design with trying to maintain system efficiency and are easy to maintain. Much of this is to do with the unique ability of water source heat pumps to share heat within a building. Many other types of systems have dedicated cooling systems and dedicated heating systems. With ClimateMaster water source heat pumps you have one simple system that shares heat.
CSE: Fire/life safety systems in mixed-use buildings often are a mixture of systems. Describe a recent project in which you provided unique solutions.
Kohler: For an on-site power system, fire/life safety circuits should be a priority and, in most cases, require a separate circuit from the on-site power system. You must always review and follow all necessary codes and standards.
CSE: Describe a unique challenge and solution for a recent super-high-rise mixed-use building project.
ClimateMaster: Due to the small size options, units can be easily concealed and individually zoned for the occupants comfort needs. In reality water source is very scalable in applications.
CSE: What types of metering or submetering solutions have you provided?
ClimateMaster: ClimateMaster water source heat pump units are perfect for submetering. Because the compressor is located in each heating and cooling unit, HVAC energy consumption can be easily measured for each individual zone. This allows for minimal association charges in mixed-use buildings and each individual tenant pays for their own actual use.
CSE: Have more mixed-use buildings been working toward U.S. Green Building Council LEED certification, and if so, how have you helped achieve this certification?
ClimateMaster: The desire for LEED certification in general is on the rise. With the high-efficiency nature of water-source or geothermal products, many LEED points can be earned just by using ClimateMaster products. In fact, we can typically achieve 19 points just through efficiency alone.