The Hybrid Concentrating Solar Thermal Systems project demonstrated the successful design, integration and operation of a high temperature solar heat (150 to 200 degrees Celsius) building space heating and cooling system, and provided a pathway for realising a world first high efficiency solar thermal desiccant air conditioning system.
Integration cost of concentrating collectors for rooftop installations
Installation of trough collectors and the desiccant air conditioner prototype on the roof required adding super structures to the roof to distribute the load onto the existing concrete columns in the roof. Structural consultants were brought in to resolve this problem. This resulted in additional project cost and time.
Remote site installation and monitoring
Heating, ventilating, and air conditioning (HVAC) tradespeople do not have expertise in emerging technologies such as desiccant systems and indirect evaporative coolers. This meant that CSIRO engineers needed to visit the site for initial troubleshooting more often than originally planned. This resulted in additional project cost and time.
Hybrid concentrating solar thermal systems for large scale applications
CSIRO’s desiccant air conditioning system prototype is between TRL3 and TRL4 and has not been built before. As a result, when HVAC contractors were asked to quote for building a prototype, they built significant costs for ‘unknown’ risks in their quotes. It is recommended that projects include a substantial contingency margin when budgeting for building prototypes that are at early TRL levels (less than TRL5) and requiring a client site installation. This margin should be facilitated by the project financier.
Hotels, shopping centres and large commercial spaces typically have a high demand for energy due to air conditioning, hot water and electricity requirements. Renewable energy technologies that operate on site can reduce energy costs and greenhouse gas emissions while increasing energy independence for the site operator.
The Hybrid Concentrating Solar Thermal Systems project developed and prototyped a new CSIRO-developed solar air conditioning technology, which was designed to provide high efficiency, low carbon heating and cooling for Australian commercial buildings. The system operated using solar ‘trough’ collectors, which were located on the roof of the Stockland shopping centre in Wendouree, Victoria.
The high temperature (150 degrees Celsius) heat collected from sunlight was used to drive a prototype high efficiency solar air conditioner and supply the building with heating and cooling. The amounts of heating and cooling generated varied to match building requirements and priorities. The ability to adapt to building needs ensured maximum benefits was delivered from the solar energy collected.
The system can be used all year round and will supply space heating in winter, space cooling in summer and hot water all year round.
This novel technology was specifically designed to operate using high temperatures and to enable high efficiency operation. This allowed maximum effect to be achieved from the collected solar heat, as the increased efficiency enabled more air conditioning to be provided from a given solar collector field.
This represented a significant cost improvement as collector fields are typically a major component of the overall project costs.
Another key benefit was that the system was able to provide multiple services in varying amounts depending upon the changing needs of the building. These valuable services are were delivered on-site and offset retail electricity costs, which were more than double wholesale energy prices. By using renewable technology savings were made on conventional energy requirements, carbon emissions could be cut and site operating costs could be reduced.
The successful completion of this project represents a step toward solar cooling technology becoming mainstream in Australian commercial buildings, thereby enabling large commercial operators to make the most of Australia’s abundant solar resources. The technology could also be used in future to generate electricity in additional to heating, cooling and hot water.
This project has demonstrated the successful design, integration of high temperature solar heat (150 degrees Celsius to 200 degrees Celsius) and operation of a building space heating and air conditioning system. The project has provided a pathway for realising a world first high efficiency solar thermal desiccant air conditioning system.
CSIRO, along with its partners, will continue monitoring the operation of the system over one annual cycle to establish long-term operation of this design. The next activities towards commercialising the technology will involve progressing the technology to technology readiness level (TRL) 6 by engineering an optimal design and collecting long term performance and life cycle assessment data in a relevant environment. CSIRO is seeking commercialisation investment to carry out these investigations and to further optimise the design for realising a thermal coefficient of performance (COP) of 1.