Comfort is performance.
High-Performance HVAC Design
Most HVAC contractors rely on rules of thumb to determine the equipment and sizing for systems they install, and the ones that do attempt a proper load calculation often lack the building science and enclosure expertise to account for all factors necessary.
On the other hand, many home performance consultants understand a systems approach to building performance, but lack the technical training and understanding to properly design and test a HVAC system to a high-performance standard.
At Velum, we are certified by the Air Conditioning Contractors of American (ACCA) to design HVAC systems and leverage our building science expertise to ensure our designs work with, not against, the building.
HVAC design services by Velum begin with full comprehension of the building enclosure as well as the desired outcomes and expectations of each client.
From there, we create computer models of your project, produce full reports from ACCA Manual J, S, T, and D, and provide detailed construction documents for proper installation.
Following the delivery of design and construction documents, we provide construction management services where we answer questions related to the installation, and perform site visits. Once complete, we also inspect and test each installation at commissioning to ensure plans and details were followed and the system is running as designed.
A well-designed HVAC system must have all four ACCA manuals processes performed along with a fully integrated building enclosure to achieve a high performance system that’s more efficient and comfortable than typical installations. Below you will find more detail about each manual.
Manual J - Load Calculation
The load calculation is used to determine the amount of heat loss and gain that is experienced throughout the year for a given building in a given climate. This is where it is imperative to take into account all aspects of the buildings enclosure assembly, foundation, insulation system, air-tightness measurement, solar orientation, door and window types, internal loads, and more.
Manual J results in a whole-building and room-by-room calculation of the amount of conditioned air is needed for comfortable heating and cooling.
Manual S - Equipment Selection
Following a load calculation, we review and select right-sized equipment to satisfy the amount of conditioned air that is required. The proper selection of equipment is paramount as every type of equipment and manufacturer of equipment has different characteristics. These characteristics such as total, sensible, and latent capacities, the amount of air volume moved, and the static pressure delivered are the key attributes. Often, oversized equipment is selected at this stage which then leads to a host of performance issues.
We will also discuss and design the need for dedicated ventilation and dehumidification or humidification depending on your specific project.
Manual T - Registers, Grilles, and Diffusers
Manual T determines how to best deliver the air throughout the room to meet the needs based on the load calculations.
The size, location, style, and design of registers, grilles, and diffusers all play a role in proper mixing of air and overall comfort of the occupants. Often times many comfort issues arise from poor choices and locations rather than the system design or equipment itself.
We work closely with architects and designers to ensure the selections are aesthetically pleasing and integrated into the overall architectural and interior design, while meeting high performance requirements.
Manual D - Duct System Design
Manual D focuses on integrating the selections to satisfy the load calculations and deliver the correct amount of air to each room with the least amount of friction and resistance.
We work with the client to determine the type of duct that is best suited for the project and design the duct system to optimize run lengths and locations, paying close attention to the types of fittings, turns, and terminations in the duct design. These details are critical as they work against the static pressure available from the blower and need to be designed and tested to ensure proper performance.