Loads Programs and GLD
GLD integrates smoothly with a number of commercial and residential loads calculation programs that are available on the market. This section reviews loads requirements and energy modeling software options for the geothermal market.
Accurate Loads Data are Essential
Accurate load calculations are the foundation of a good geothermal heat exchanger design. Historically, engineers have been conservative in their loads analyses and have oversized loads. With traditional HVAC equipment oversizing is not particularly expensive. With geothermal systems however, oversizing is prohibitively expensive because ground loops are costly. Consequently, it is well worth the effort to calculate an accurate loads profile that takes internal gains and building diversity into account.
Loads Requirements for Commercial Geothermal System Design
At a minimum, peak hourly loads (kBtu/Hr or kW) and annual loads (total kBtu or total kWh) are required for accurate design work with GLD. This is because as heat is rejected to and withdrawn from the soil, the soil temperature changes. Modeling this temperature change accurately is essential to designing a stable geothermal heat exchanger. Energy/annual loads calculations may be unfamiliar to commercial designers new to the geothermal field. Read the following documents to learn more:
- General Loads Information
- Design Day, Monthly and Hourly Loads
- Benefits of 8760 Hourly Energy Modeling
Commercial Loads Program Integration with GLD
Below please find information about loads and building simulations programs that provide both the peak and cumulative/duration loads necessary for geothermal design.
Trane Trace 700/System Analyzer
- GLD and Trane Trace Overview
- Hourly Data Profiles and Trane Trace
- Video from Trane regarding geothermal design
LEED/GreenGlobes Certification and GLD
Hour by hour analysis is essential for calculating points for LEED (Leadership in Energy and Environmental Design) certification. GLD can model the system hour by hour for any vertical loopfield design to determine hourly loopfield temperatures and energy usage.
Designers may also use 8760 hour data from other loads programs. Any program that can export a file such as .csv, .xls or .txt file can supply data to GLD.
Residential Loads Programs
Residential designs require peak hourly (kBtu/hr or kW/hr.) and energy/annual loads (total kbtu or total kw). In GLD, this energy/annual load is formatted as a run time fraction. Most residential load programs output peak data while very few output energy/annual load totals. LEAD PLUS, a program that calculates peak and energy loads, integrates effortlessly with GLD. For more information on LEAD PLUS and GLD Residential version, click here.