For the first time it has been necessary to monitor solar thermal performance on a daily basis in order to provide proper billing and performance review. Previously metering was simply not completed and the owner had no idea whether the solar system was performing or not. This undoubtedly led to client frustration when systems did not appear to be impacting utility bills as anticipated.

No solar thermal-specific data monitoring or metering equipment existed at any scale in North America prior to the build out of Mondial’s projects. Mondial therefore sourced its metering capabilities from Europe. First of all Mondial focused on small scale district hot water heating metering calculators as the key data acquisition component: flows and temperatures are consistent with those found in typical solar thermal installations. Secondly the market for flow meters available in North America is focussed on industry use and their typical high flow rates for a given pipe diameter, whereas low flow measurement is crucial in capturing all the flow and therefore available revenue in solar thermal. Imported flow meters have permitted capturing a single fixture unit (e. g. a shower) in a 50mm domestic hot water pipe, rather than having the meter cut out due to low flow conditions.

Another key aspect for Mondial has been the ability to demonstrate to our clients their system’s energy production in real time. Mondial worked with a leading renewable energy metering company to modify their existing solar electric systems to work with thermal meters. The result has been the first real time monitoring of solar thermal systems in North America.

This has permitted client-friendly readings of carbon offsets and easily understood energy generation details.

Crucially for Mondial this data acquisition has permitted ongoing refinement of system design; minute by minute flow data has provided accurate usage profiles for different building types while domestic cold water temperatures have allowed model input data to properly reflect system behaviour over time.

Additionally Mondial has been able to take this data and prove coincidence between hot water usage in multi-residential buildings and peak electrical system load days. While intuitive, we have been able to demonstrate that peak electricity consumption coincides with peak solar activity at the exact hours when the system is under strain, and that during these key peak hours Mondial’s storage tanks and hot water delivery temperature grade ensure that electric hot water heaters are not in operation. This means that investment in solar thermal for a building with electric hot water heating can directly offset requirements to invest in new power plant production and constitutes a fuel switch strategy away from electricity, without the need to move to natural gas or other carbon- based sources.

Finally remote metering allows Mondial to view energy generation monthly on line and issue invoices without the need to visit sites, eliminating geographic constraints for system installations.

1.3. Commissioning

Analogous to the green building movement currently gaining momentum in North America, solar thermal systems simply do not perform well unless thorough commissioning takes place during the design, construction and operation phases. For Mondial this has meant reviewing our suppliers’ designs during the energy modelling and design stages, and also helping them modify system specifics (collector numbers, storage volumes) based on experience gained from Mondial’s pre­existing data. During build out Mondial now has access to real time performance data permitting peak and transitional collector performance review. This has provided the contractor the ability to optimise flows to ensure resulting energy capture.

From a financial point of view Mondial also needs to understand how its systems perform compared to their predicted energy models, on which investment decisions are made. Ongoing data review results in refined performance models that contribute to better performance certainty, and therefore economic predictability. This is inherent risk mitigation from our funders’ point of view.

1.4. Maintenance

Mondial’s success depends on ongoing system performance. Mondial has therefore had to develop maintenance specifications and negotiate annual maintenance contracts with providers. Again this is an activity that had not been completed at any scale or replication in the solar thermal industry.

1.5. Conclusion

In moving to a Power Purchase Agreement model for the delivery of solar thermal energy, the necessary advancements in metering, data acquisition and commissioning have pushed the solar thermal industry to new heights of service, quality and energy delivery certainty.