High expectations for high-performance buildings: sustainable buildings/energy efficiency

High-performance buildings are intricate, complex projects that require attention—qualified, expert consulting-specifying engineers apply their knowledge on such projects specifically within the sustainable buildings/energy efficiency segment.

By Consulting-Specifying Engineer June 23, 2017

Respondents

  • Dave Clute, NREL Energy Executive, BOMI-HP, VP, Intelligent Building Group Operation Director, Environmental Systems Design Inc., Chicago
  • Paul Erickson, LEED AP BD+C, Building Performance Practice Leader, Affiliated Engineers Inc., Madison, Wis.
  • Richard Holzer, PE, NCEES, LEED AP BD+C, HBPD, Principal Engineer, Southland Industries, Garden Grove, Calif.
  • Tim Kuhlman, PE, RCDD, CDT, Associate Principal, TEECOM, Portland, Ore.
  • A. Brian Lomel, PE, LEED AP BD+C, CxA, WELL AP, Director, TLC Engineering for Architecture, Orlando, Fla.

CSE: Energy efficiency and sustainability are frequent requests from building owners. What unusual net zero energy and/or high-performance systems have you recently specified on high-performance facilities (either an existing buildings or new construction)?

Erickson: There is a long list of great strategies applicable to campus projects, some of which include fixed shading systems, electrochromic glazing, LED lighting with integrated daylighting controls, occupancy-controlled receptacles, high-efficiency user equipment (office, medical, labs), operable windows, ceiling fans, radiant heating and cooling, chilled beams, VRF systems, DOAS with integral energy recovery, enhanced runaround-loop energy recovery, indirect-evaporative coolers, heat-recovery chillers, ground-source heat pumps, variable-speed air-cooled chillers, solar hot-water arrays, and PV systems.

Clute: Masdar headquarters was designed not only as a net zero high-performance building, but as the first positive-energy facility in the Middle East. ESD incorporated:

  • Concepts of indoor climate control (specific to the desert region)
  • PV panels that maximize air movement and shading
  • Towering wind cones that exhaust warm air out
  • Rainwater collection/greywater recycling to maximize water conservation.

The underfloor air-distribution system used for the HVAC system reduces energy use due to the natural air buoyancy created by convection-propelled vertical air movement. Since wet-bulb design temperatures intrinsic to the region are extremely high, special attention was given to the sizing of cool coils as well as the desiccant energy-recovery ventilation system to provide dry, conditioned air. The technology system was designed as IP-based and for a high level of building systems integration to maximize efficiency and flexibility, which reduces the need for redundant systems throughout the facility.

Holzer: Southland recently completed a near net zero energy-maintenance and operations facility for the Los Angeles Community College District. This project employed solar systems for both electricity and heat production (hot water). Hot water produced from the solar collectors is stored in a large underground tank for use in space heating and air conditioning. The HVAC system includes heat-driven absorption chillers to produce chilled water for air conditioning.

CSE: What types of sustainable features or concerns might you encounter on a high-performance building that you wouldn’t on other projects?

Kuhlman: One sustainable feature implanted on high-performance data centers is to use free air cooling in the server halls. This uses filtered outside air to cool the servers. The hot exhaust air is contained and ducted outside the building. This avoids the need for a chiller plant and significantly reduces the data center energy usage. All this outside air in the server halls can be a challenge to the materials being selected. Temperature and humidity can vary the same as it does if the equipment was outside. For some of these high-performance data centers, the lifespan of a server is about 2 to 4 years. However, the building systems need to last much longer.

Erickson: Most engineers and operators suggest using the “keep it simple” principle. This is easier said than done as new systems are added to a campus portfolio. Improved and additional training are a starting point. Improving BAS graphics offers an additional means to help operators interpret performance of new systems. Fault detection and diagnostics capabilities also can be activated for most leading BAS software. The design engineer and operators working together to optimize FDD value will go a long way toward making system operations more effective.

CSE: What types of renewable or alternative energy systems have you recently specified to provide power for such projects? This may include photovoltaics, wind turbines, etc. Describe the challenges and solutions.

Holzer: I’ve used a lot of solar PV systems, solar hot-water systems, and on a recent project, a utility-scale wind turbine to produce electricity. We have completed buildings using ground-coupled geothermal heat pumps and currently are finishing a project using a sewage-waste energy-exchange system that allows heat reclaim from relatively warm sewage effluent from the building.

Clute: We worked on Suzhou Golden Land in Suzhou, China. Designed for LEED Gold certification, this mixed-use complex is comprised of a 65-story office/hotel tower, 58-story residential tower, and a 940,000-sq-ft multistory retail podium with belowgrade parking. Energy-conserving features include a green roof and raised pavers on the podium, guest room vacancy controls to minimize heating/cooling/lighting, BMS-linked smart submetering, high-efficiency lighting, heat-recovery chillers to preheat the domestic hot-water load from chillers, a water-side economizer, heat-recovery ventilation on outside-air fans, water-conserving sanitary fixtures, greywater collection from lavatories and showers, and condensate collection from the hotel for cooling tower make-up water. We performed the following solar energy studies to inform design:

  • Analysis to determine the amount of solar PV coverage on the south, east, and west facades required to meet Chinese Energy Code and LEED V4 EAC5 (renewable energy credit).
  • Podium-roof radiation study to identify PV placement for optimal power production.
  • Façade analysis to determine the optimal solar radiation and shading levels at different heights of the building’s curved form.

Erickson: PV and solar hot water are the systems we’re typically specifying, including BIPV. We’ve attempted roof-mounted wind turbines with minimal success. Ground-mounted turbines have been much more successful, in our experience.

CSE: What future trends are you anticipating for more sustainable, high-performance buildings?

Lomel: You don’t have to invest in wildly expensive, complex systems if the design team is really working well together and uses energy modeling from the outset to reduce the overall demand of the building. Educating the people who will occupy the building to work with the building will result in a better outcome than a sophisticated design. The most high-performance buildings are the simplest and easiest to use.

Holzer: With increasing interest in net zero energy buildings and increased urban building density, district energy systems are seeing increased interest. District-level systems allow for the sharing of renewable solar photovoltaic electricity via microgrids as well as thermal energy-transfer between buildings using hydronic water loops.

Clute: The following are trends we see as becoming more important for sustainable, high-performance buildings:

  • Sustainability and green-building consulting: Green rating systems were created with the intent of reducing building energy use, conserving natural resources, and promoting healthier indoor environments. These systems will become more common.
  • Benchmarking and Energy Star: Documenting the building characteristics required for accurate benchmarking and applying for Energy Star certification with minimal review from the U.S. Environmental Protection Agency.
  • Energy auditing: The first step toward making significant energy efficiency improvements is identifying the opportunities to provide the framework for both low-cost and capital-intensive retrofit projects.
  • Energy analytics: Incorporate both architectural and engineering components for true integrated design and accurate results for investment-grade audits.
  • BAS design: Increased reliance on building automation systems that monitor and control independent mechanical, electrical, and technology systems to allow for a holistic approach to operating a building.
  • Energy efficiency project-funding documentation: Government and utility organizations offer various incentives, grants, and tax deductions to support energy-efficient projects in facilities across the U.S. Identifying and securing funding through programs, such as ComEd Smart Ideas, commercial buildings energy efficiency tax deductions and bonds, and renewable energy grants, will become increasingly important.
  • Renewable energy feasibility studies: Location-specific feasibility studies will become more important to validate the effectiveness of these renewable technologies.