Design Development (65%)
The design development (65%) phase is a progression where changes from the schematic design phase are incorporated and further details are developed on building systems. In this phase, the architectural and engineering (A&E) firm typically starts to present overall costs associated with the design. As with the each design phase, the current design will be reviewed by the design team, and the agency should ask the A&E firm to substantiate how the included measures meet design requirements for energy.
Design development is when the size and design of the specific renewable energy technologies is accomplished. It is important to evaluate the design to ensure that the particular technology can be incorporated into the project as intended.
If it has not already occurred, the design team needs to be expanded to include any subcontractors hired by the A&E firm or the agency to handle the design of renewable energy systems.
As the project continues to develop, it is increasingly important to ensure any concerns from all disciplines are discussed and alleviated as changes become increasing likely to affect the project schedule and/or budget. Although some technologies may still be eliminated from consideration for cost or performance issues, no new renewable energy technologies are likely to be added or considered at this phase.
Often, A&E firms will not have the specialized expertise and certifications warranted for designing a particular renewable energy system. The agency or the A&E firm can contract for these services directly through engineering, procurement, and construction (EPC) contracts to have technology specific experts design the renewable systems directly. In these cases, system designs needs to be carefully coordinated with the primary design team to identify any concerns, overlap, or discrepancies. While not exhaustive, some specific items to review include:
- Structural design to ensure it is designed to handle the required photovoltaic or solar hot water panel load for roof-mounted systems.
- Space in mechanical and/or electrical rooms to ensure space for inverters, storage tanks for solar hot water, or any other renewable energy system equipment needed to complete the system has been included.
- Energy simulations to ensure that the associated electrical and thermal demands, usage, and projected costs are aligned with project goals.
While some aspects of the design, including final glazing selections or specific mechanical system components, may yet to be finalized at this point in the design process, many major components will likely be identified. An EPC contract has the advantage of not specifying particular equipment models far ahead of actual installation. In some renewable energy fields, such as photovoltaics, the production and availability of specific models may vary with time but many options are available to produce the same result.
For projects attempting to offset a certain percentage of its annual energy with renewable energy technologies or to meet a specified annual energy use target, it is increasingly important to use targeted engineering calculations or whole building energy simulations to ensure the technology can meet specified project goals.
Engineering calculations, load sizing output, and/or whole building energy simulations reflecting current design, as well as measures to further increase the overall building efficiency, should be reviewed at this and all other phases of the design process. At this phase of the project, many of the architectural features, mechanical system components, and internal loads have been developed to a point where it is possible to better understand their impact on project goals.
Separate energy simulation files should be preserved at each phase of the design that reflect the design documents at that point in time. Any changes incorporated into the current model should be documented with the simulation files. Changes may include operating schedules, architectural components, mechanical system components, or other energy end use systems, including process loads, that may not have previously been identified.