- How is backpressure handled?
- Do you have to take the customer’s facility down to install your system?
- What is the operating runtime of your machines
- Where has this technology been demonstrated before
- What is the anticipated useful life of the machinery used in the system?
- How do you perform/handle maintenance and what does that cost?
- What type of daily operation is required of the machine?
- What is the footprint?
- What kind of generator do you use and how do you interconnect to a customer’s system?
- What is the refrigerant used in KGRA’s system?
- Do you use a surge protection tank?
- Is the energy produced by a KGRA system considered “renewable energy?”
- What is the capital cost of a system?
- How do you handle flue gasses that contain sulphur and/or other undesirable chemicals?
- What is the lowest temperature to which you can take the waste heat source temperature?
- How does KGRA evaluate a customer’s waste heat source?
- Why hasn’t heat recovery been done before?
- How long does it take to install a system?
1. How is backpressure handled?
KGRA recognizes that its customers operations may be extremely sensitive to backpressure and as such, engineers its heat recovery systems to fall within customers’ allowable pressure drop ranges
This can be accomplished in a variety of ways but the two most common methods are to 1) increase surface area on the heat recovery unit, and 2) implement an induced-draft fan.
Increasing the surface area is not typically a difficult exercise and precise measurements can be made to anticipate the inches of water column a KGRA design will have. A representative diagram of a bypassable heat recovery system designed to meet a customer’s strict backpressure requirement is found below. 
2. Do you have to take the customer’s facility down to install your system?
All of the foundations, electrical connections, piping, and other civil engineering is typically performed in the weeks leading up to the packaged ORC system’s delivery. This can all take place while the customer’s facility is running.
Upon delivery of the ORC, waste heat recovery unit, and condenser system, the construction team places the units on their respective foundations and interconnects the relevant piping and wiring systems.
The waste heat recovery unit is the only device that interfaces with the customer’s production system, and KGRA schedules its tie-in to coincide with a planned facility shut-down.
3. What is the operating runtime of your machines
The machinery KGRA uses in its systems have a demonstrated availability of over 98% in the field.
4. Where has this technology been demonstrated before
ORC-based waste heat recovery systems have been successfully deployed at refineries, glass plants, cement plants, gas treatment plants, gas transmission stations, biomass facilities, and lumber mills. There are over 150 installations around the world, many of which have been operating for over a decade.
5. What is the anticipated useful life of the machinery used in the system?
KGRA’s ORCs have an anticipated useful life of 20 years.
6. How do you perform/handle maintenance and what does that cost?
Many customers opt to outsource 100% of the maintenance of the ORC and the associated equipment to KGRA and its affiliates. In this way, KGRA is responsible for all of the routine, break-fix, and major overhaul maintenance on the system. KGRA’s systems are equipped with “phone home” capabilities – enabling seamless operation and remote maintenance. Customers with existing on-site support teams can also opt to handle maintenance themselves. In this instance, KGRA will arrange for training so that the customer is fully prepared for all maintenance requirements. In either instance, KGRA can export real-time data from its operator control system to interface with a customer’s control room, providing the customer’s operations/maintenance crew with a real-time look into all the relevant metrics.
7. What type of daily operation is required of the machine?
KGRA’s systems are designed to operate without any ongoing onsite operator intervention since all of the system’s attributes are handled by the automated control system. At the same time, the system can also be manually controlled via the onboard operator interface. Start-up and shut-down procedures can be quickly and easily handled by onsite operators through the control system.
The ORC is skid-mounted and has a standard base of 15’ x 35’. Depending on the type and quality of the heat source (which helps determine the amount of surface area needed to evaporate the working fluid), the evaporator/heat exchanger may extend beyond the skid’s base. If space constraints are an issue, the system can be custom engineered to fit into the customer’s available space.
The size of the condensing system is dependent upon whether the system is cooled via water or air. Generally speaking, water-cooled systems have a 10’ x 10’ or 15’ x 15’ footprint, whereas air-cooled condensers are substantially larger and scale linearly with the size of the ORC. A 1MW ORC would require a cooling system with a 20’ x 60’ footprint whereas a 10MW ORC would require a cooling system with a 100’ x 60’ footprint. Lube oil and motor control center systems can be housed attached to/onboard the ORC to conserve additional space.
9. What kind of generator do you use and how do you interconnect to a customer’s system?
KGRA’s systems are modular, scalable, and customizable. As a result, generators of all types and varieties can be specified into KGRA’s systems to match customer’s requirements. Further, KGRA retains responsibility for all aspects of the electrical interconnection process.
KGRA’s system does draw a small amount of power from the customer’s grid during start-up (prior to when the turbine generator produces electricity). This consumptive power load is metered and offset against the power produced by KGRA, resulting in the net power sold.
10. What is the refrigerant used in KGRA’s system?
In projects where the heat source is greater than 500F, KGRA typically installs an interposing oil loop containing a DOWTHERM or Therminol heat transfer fluid. This fluid is circulated in the heat source and transports the heat to KGRA’s ORC to evaporate the ORC working fluid. INSERT WHATEVER ORMAT’S ARE AND OTHERS
Most of KGRA’s ORC projects use a working fluid called R245fa (chemical name: 1,1,1,3,3-pentafluoropropan). The vapor point for this fluid is approximately 59F. In certain lower temperature projects, KGRA uses a working fluid called R134a (chemical name: 1,1,1,2-Tetrafluoro).
11. Do you use a surge protection tank?
Yes, on nearly all installations, KGRA installs a surge protection tank for its working fluid. Where relevant, this can be oversized and housed in a special containment system for safety purposes.
12. Is the energy produced by a KGRA system considered “renewable energy?”
This is dependent on the location of the project. In many instances this will qualify as renewable, energy efficiency, or both. Outside of the US it can qualify for carbon credits under the Kyoto Protocol.
13. What is the capital cost of a system?
Capital costs are very project-specific and depend on several key factors:
- Size (larger projects are more capital efficient than smaller projects)
- Ambient conditions
- Access to cooling water
- Whether heat will be recovered from gaseous streams or liquid streams
- Complexity of the installation
Once a customer has provided KGRA with the necessary inputs, KGRA will run performance and cost modeling scenarios and will share the results with the client.
14. How do you handle flue gasses that contain sulphur and/or other undesirable chemicals?
KGRA engineers its heat recovery systems to specifically match the requirements of each project. In instances where undesirable chemicals may precipitate out of the gas stream as its cooled in KGRA’s heat exchangers, special care will be given to materials selection and equipment needed to collect and process the waste streams. KGRA’s engineers have extensive experience in handling projects with this added layer of complexity.
15. What is the lowest temperature to which you can take the waste heat source temperature?
This is entirely dependent upon what the heat stream contains. KGRA evaluates each project individually and makes recommendations to its customers based on the optimal price/performance intersection. Cooled temperature and the cost of cooling is a substantial factor in this consideration.
KGRA has participated in projects where fluid streams are to be cooled as low as 120°F.
16. How does KGRA evaluate a customer’s waste heat source?
KGRA has questionnaires specifically designed for each of its served industry verticals. These questionnaires gather the relevant information needed to properly evaluate a heat source for its physical and economic viability. KGRA has developed proprietary modeling software that converts these inputs into usable evaluation data.
After initial screening, KGRA will typically have follow-up questions for the customer which are usually handled via email or phone call. As a project continues to progress, a site visit is scheduled so that a full evaluation of the facility and any implementation complexities can be ascertained.
17. Why hasn’t heat recovery been done before?
Low temperature heat recovery has been done many times before in a variety of industry settings and around the world. However, adoption has recently begun to accelerate due to KGRA’s turnkey project approach and to changes in the way ORC systems are packaged (modular, scalable approach).
18. What is the timeframe for installing a system?
Depending on materials availability, projects typically take approximately 50 weeks to be completed from the time equipment is ordered. The majority of this time is for the construction of the ORC, which is factory-built. Onsite construction (typically limited to concrete pads and any support structures) is typically 1 week and occurs just prior to equipment delivery. Assembly and interconnection of the waste heat recovery unit, ORC, cooling system, and electric is typically another 1-2 weeks with commissioning requiring 1-2 weeks.
