Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - Hot chips (Waste heat recovery for industrial heat intensive processes)

Teaser

What is the problem/issue being addressed?More than 50% of all power generated in the World is lost to the environment as waste heat. Heat intensive production processes, such as food, beverage and consumer product production, represent a considerable part of the energy...

Summary

What is the problem/issue being addressed?
More than 50% of all power generated in the World is lost to the environment as waste heat. Heat intensive production processes, such as food, beverage and consumer product production, represent a considerable part of the energy consumed by industry. Heat for e.g. frying, drying, sterilizing, cooking of pasteurizing is most often delivered by boilers burning fossil energy – mostly natural gas in Europe.
Many such processes are operated 24/7, all year round. Here heat generation constitutes a significant part of the overall production cost, and adds to the industry’s negative environmental impact.
Heat pumps, recovering waste heat from a process and upgrading it to a higher a temperature in order to use it again in the same process, are widely used in industry. Such heat pumps have unitil now not been able to efficiently deliver output temperatures much in excess of 120 oC. This is not sufficent for e.g deep frying processes in the food manufacturing industry, who require temperatures approaching 200 oC.
Duynie Group, a Dutch agritech company, has patented a high temperature heat pump design to for waste heat recovery in deep frying processes, particularly for production of French fries or potato chips. Tocircle’s proprietary compressor technology is an essential part of this heat pump design.
Deep frying of potato produce is a first, well defined application which will be used within this project to test Tocircle’s compressors in a real industrial environment, bringing the technology from TRL 6 to TRL 9 (Technololgy Readiness Level). There are however many other similar applications, both in the food industry and e.g. in pharmaceutical production and chemistry, that can be addressed by this high temperature heat pump technology.
The issue being addressed is thus waste heat reconditioning in high temperature (160-190 oC), heat intensive industrial production processes. Reconditioning meaning that the thermal energy contained in waste heat from the process is upgraded to the original temperature that the process requires, so as to be re-used in this process.

Why is it important for society?
Increasing the energy efficiency of such continuous industrial heat intensive production processes, so reducing their energy cost and their environmental footprint, has several positive consequences: potentially cheaper products for the consumer, lower carbon emissions, and finally better Corporate Social Responsibility (CSR) image for the producer.
Achieving better use of the energy consumed in continuous industrial processes (often running at full power in excess of 8000 hours per year) has potentially a much higher lifecycle value than solar or wind energy, which only generate at full rating during a few thousand hours annually.
Considering the case of potato frying, this is a large industry segment that in Europe alone yearly consumes some 8TWh of energy, at a gas cost of 210 M€ while emitting 1.5 milllion tons of CO2. Decreasing the gas consumption of such production will reduce its cost and environmental impact, which constitutes an important benefit for both producer, consumer and society at large.
Applied to other market segments and other production processes, the technology will deliver similar advantages to society.

What are the overall objectives?
The primary technical objective of the “Hot Chips” project is to verify the performance of Tocircle’s controllable rotary vane compressors demonstrated in real conditions in a full-scale, high temperature heat pump for waste heat recovery in industrial deep-frying of potato produce.
Commercially, the objective is to deploy a sales and service offering for high temperature heat pumps, which will act as a sales channel for Tocircle’s controlled rotary vane compressors. For the end customer this should reduce production energy cost by up to 50%, including reductions in carbon tax levies.
The main environmental objective is to

Work performed

Work performed
A scaled-down Pilot heat pump process skid (DTC-1500) was installed at Tocircle’s test center in Glomfjord in May 2018. This skid has allowed an earlier start of testing of both heat pump functionalities and compressor performance than initially planned.
The compressor assembly for the Pilot heat pump has been completed and the heat pump skid has been commissioned with water as working medium. Durability issues in the 2nd stage compressor were identified, which has led to design optimizations and production of an enhanced high pressure compressor unit.
The Pilot heat pump has to this date been run in excess of 400 hours with the low pressure stage compressor, which has been very useful for debugging and optimizing work.

Main results
- Achieved early debugging of heat pump control software and hardware optimization, results of which are both directly transferable to the future full-scale heat pump.
- Identified durability issues for the 2nd stage compressor, leading to design changes and fabrication of a prototype unit delivered in April 2019.
- Selected suppliers and established a supply chain for fabrication of Tocircle’s controlled rotary vane machines (compressors).
- Initiated preparations for installation of the scaled-down Pilot heat pump at a designated French fries production facility in Belgium owned by Aviko BV, a sister company of Duynie Group.

Final results

Progress
Achieved heat pump output temperature of 140 oC with a single low pressure stage compressor, and with a COP of 5.4 (Coefficient of Performance). The high pressure stage compressor has been tested up to 188 oC. Due to the compressor’s multiphase capability, compression is performed without losses due to overheating of the working medium, which in this case is pure water. Better performance still is expected using a water/ammonia solution.

Expected results
On completion of the redesigned high pressure compressor unit in May 2019 the 2-stage compressor assembly shall be completed and it is expected that factory testing shall demonstrate the capability to deliver a 180 oC output temperature. The Pilot heat pump will be tested both with water as working medium and with a water/ammonia mix.
The expected results for the Pilot installation is to prove that the heat pump is capable to lift the frying oil back to the needed temperature of 180oC. The pilot is however by its nature too small to serve a full-sized industrial potato deep-frying line.
The expected result of the full-sized heat pump to be built in 2020 is to demonstrate both temperature lifting capacity, and volume capacity sufficient for a full size frying line. The main difference, besides a threefold increase in volume capacity, being that the full size compressor assembly consists of three compressors operating in parallel (low stage) plus one high pressure compressor (high stage). The Pilot, in comparison, only uses one low stage and one high stage compressor.

Website & more info

More info: https://www.theexplorer.no/solutions/Tocircle-World-class-technology-for-waste-heat-recovery/.