Concept Design Steps to Reduce Embodied Carbon
Mechanical System:
1) Design for high R-value insulation to minimize mechanical unit equipment sizes.
2) Optimize the air distribution system with the mechanical engineer to minimize ductwork.
3) Use natural ventilation.
4) Efficient Distribution: Smaller ducts and pipes require less material, directly lowering the production-related carbon footprint. Optimizing the layout to minimize the length of pipe and duct runs is a high-impact, low-cost strategy.
5) Low-GWP Alternatives: Specify systems that use natural refrigerants (like CO2 or ammonia) or low-GWP alternatives such as R-32 or R-454B.
6) Leakage Prevention: Design systems to minimize the number of joints and connections where leaks typically occur, and implement robust refrigerant tracking and management programs.
7) Consider the use of water as a heat transfer medium in lieu of refrigerant when considering split systems or VRV/VRF. There are hybrid refrigerant to VRV/VRF systems that distribute water, rather than refrigerant, which would decrease refrigerant leakage emissions over time.
8) Consider use of low temperature heating hot water to allow for use of air source heat pumps to replace boiler plants now or in the future.
9) In chiller plants, consider using 1233zd or 1234ze ultra-low GWP refrigerants.
10) Always consider load reduction in the passive building envelope as the way to decrease mechanical system size and therefore the amount of equipment material, distribution system material, and refrigerant and ultimately operational carbon.
Electrical System:
1) Specify switchgear that uses alternative insulating gases(to SF6, sulfur hexafluoride) or vacuum-solid dielectrics to eliminate fugitive emissions.
2) Select transformers with optimized core materials, such as high-grade silicon steel, to reduce energy losses. Products like Hitachi Energy's EconiQ can reduce material-related emissions by up to 35%.
3) Digital Integration: Use "smart" or digitally integrated circuit breakers. These are often 25% smaller than traditional units, reducing the total mass of the distribution system.
4) Circular Design: Specify distribution boards and panels designed for modular upgrades and disassembly. This allows individual components to be replaced or recycled at the end of their life rather than discarding the entire unit.
5) Use fewer luminaires by optimizing for daylighting and task-specific lighting rather than uniform high-level illumination across all spaces.
6) Modular Components: Ensure drivers and LED modules are easily replaceable or upgradeable without discarding the entire fixture.
7) 3D Printing: Innovative techniques, such as those used by Signify, can result in luminaires with up to a 75% lower carbon footprint compared to conventional production.
8) Use AI-Driven Routing: Advanced design tools, such as those from Schnackel Engineers, can optimize electrical distribution routing to find the most efficient path, reducing material and labor by 10% to 30%.
Plumbing system:
1) Use HDPE piping where possible. HDPE piping has 52% less embodied carbon than concrete or steel and 36% less than PVC, and HDPE is recyclable.
2) Prefabrication and Modularization: Standardized, preassembled pipe spools and modular units can reduce field joints and material waste by up to 53% according to industry surveys.