Thermal Products

The Delphi Solar Heat Exchanger is an important component in a cooperative effort between Delphi and a solar energy company to develop and deploy cost-effective renewable energy options. Although solar thermal power generation is not a new concept, the marriage of this approach with an economics-driven system design yields a novel value proposition. The entire system is constructed of readily available, proven components.

The system is based on the well-known Rankine Cycle. The system converts sunlight into heat, which is used to run a vane expander connected to a generator that produces ready-to-use 480/3-phase power. This mechanical approach differs from solar photovoltaic systems that directly convert sunlight into low voltage DC power chemically. In contrast to other solar thermal entries, the system operates at low temperature and pressure, which provides for easy installation and operation. The system can be installed in locations where other solar systems are unable to perform at the same efficiencies.

The solar energy company uses an inexpensive flat panel type heat collection system to raise the temperature of a working fluid to between 150°F and 200°F (65°C and 93°C). This working fluid then heats a proprietary refrigerant to boiling. The resulting high-pressure vapor is run through an expander in a secondary loop connected to a standard three-phase induction generator that can generate 30 kW of AC electricity during peak periods.

The Delphi Solar Heat Exchanger is prominently featured in a collector unit, and serves the primary purpose of heating the working fluid to levels sufficient to vaporize the refrigerant housed in the secondary loop. The Delphi Solar Heat Exchanger harnesses the sun's power and drives the entire system.

Power output can be maintained 24 hours per day by utilizing a conventionally fueled topping cycle. This topping cycle can be fueled by propane, gas, or methane and is run during periods of cloud cover or during the night to level the output from the power plant. In many locales, there are allowances for topping cycles that do not jeopardize the system status as a renewable power source. This is important as there are numerous incentives and pending legislation intended to hasten the adoption of renewable power. 

Additional benefits are attainable with slight changes to the system's configuration. For example, the addition of surplus collector panels to a system affords the opportunity to store hot water generated during daytime running hours for usage at night, thereby reducing the power consumption associated with heating water for domestic or other uses.

Benefits

The system provides an attractive alternative to traditional power generation systems because it:

• Uses off-the-shelf components to minimize cost and enhance reliability and up-time
• Takes advantage of the proven performance of a simple, low-temperature, low-pressure Rankine Cycle to produce renewable energy at market prices
• Is comprised of a 25-30 kW modular cell, which can be replicated as necessary to meet demand requirements; this modular design allows for negligible output loss due to field issues
• Requires minimal non-technical maintenance that can be performed by heating, ventilation, and air conditioning (HVAC) technicians
• Promotes environmentally friendly power generation
• Demonstrates a sustainable strategy for the production of "green" energy and helps reduce dependence on fossil fuels

Solar Collector

Typical Applications

The system, inclusive of the Delphi Solar Heat Exchanger, is suitable for a wide variety of applications and is targeted for use in areas where land is inexpensive and available. This is not intended for rooftop applications and is available only to wholesale customers such as utilities and large retail customers like corporations and manufacturing facilities. It is ideally suited for distributed generation applications, remote sites, or relieving congestion issues.

The system can be purchased outright by customers who wish to own the equipment and use and/or sell the generated power, or it can be installed and operated under a power purchase agreement that affords the customer the ability to purchase the power produced without owning the asset.

Performance Advantages

The low-pressure, low-temperature system, which includes the Delphi Solar Heat Exchanger, offers an innovative and affordable alternative to the growing need for renewable and alternative energy sources in an increasingly power-strapped world.