Feasibility study on waste heat utilization, where the possibilities were analyzed for exploiting the waste heat to produce heat for space heating, cooling or the production of electricity.

The situation

The company ETI Elektoelement d.d. is one of the world’s leading manufacturers of solutions for residential and commercial installations, power distribution for low and medium voltage, power electronics and semiconductors, as well as producing technical ceramic products, tools, equipment, and plastic products.

Business challenge

ETI Elektroelement’s effort is to enhance flexibility and competitiveness in the conquest of new products, so the profits are invested in knowledge, markets and technological development.
They planned the technological development with the knowledge that in the field of optimization of the heat supply, there are untapped potentials of gas furnaces, low level of energy self-sufficiency and the high cost of space heating.
Despite identifying opportunities for greater exploitation of the potential flue gases heat in gas furnaces, the company faced a challenges in identification of appropriate solutions due to the lack of information (such as time randomness of some technological processes, unknown dynamics of the demand for heat and cooling, unknown costs and economic efficiency of the project). As an adequate they recognized the goal of increasing energy efficiency and lowering operating costs of energy supply.
Due to the complexity of the solutions and the high dynamics of the devices operation, the classic methodology for the design of energy plants (on the basis of nominal power, the annual number of operating hours, etc.) did not prove to be adequate – they needed a more detailed analysis with a computer simulation of the possible solutions.
Continuation of the existing system of heat supply presents a risk of reducing the competitiveness, lower economic performance of the company and increasing dependence on (high) energy cost. Without a detailed feasibility study for exploiting waste heat, they would not have had a clear vision of technology development for optimization of heat, which also makes high-quality execution of successive steps (preparation of project documentation, tender for implementation review and preparation of candidacy for grants and calls for efficient energy use, etc.).

Reasons

• There is waste heat from the furnaces, but it is unclear whether it is possible and economically justified due to the dynamics of the production process in furnaces and dryers.
• Reducing the cost of supply of heat (heating).
• The economics of the different solutions was unclear, because many variable factors, such as. climatic conditions at the location, availability (in time and power) produced by waste heat, etc.
• Waste heat for cooling in the production of technical ceramics in summer (absorption chiller).
• Unclear interdependence and correlation among various possible solutions for waste heat recovery.
• Reducing the cost of electricity by own production using waste heat recovery system (ORC).

Capabilities and solutions

A feasibility study for utilization of waste heat was conducted, where there were considered the possibilities of exploiting the waste heat to produce heat for space heating, cooling or the production of electricity. The feasibility study consists of the following topics:

• Detailed computer simulation of a combined energy system for a period of one year, based on the one-hour intervals and real climatic conditions.
• Identification of the potential of waste heat.
• Comparison of energy indicators of the current state with indicators that could be achieved by the implementation of the proposed systems for waste heat recovery under the same conditions (eg. in the same year).
• Description of necessary modifications of the existing system.
• Estimated costs of the investment.
• Economic analysis (simple payback period, internal rate of return, net present value).

Inea, with the comprehensive study, acquainted investor with the existing situation and evaluation of the technical and economic potential for the implementation of further steps.

Results

• Proposal and design of an appropriate system of heat recovery.
• Calculation of energy savings for individual and comprehensive investment study, the calculation of profitability (net present value, ROI, a simple payback period of the investment, …).
• Clear guidelines for the high-quality project documentation.

Ivan Lavrač, project engineer, employed in the development of technical ceramics in ETI Elektroelement d.d., said:

“Engineers from Inea successfully carried out the feasibility study for the exploitation of heat from the flue gas chamber furnace at the plant in Izlake. They showed a professional approach to the manufacture of single study, their work is carried out professionally and in the required time. Detailed computer simulations of possible operating systems with the economic analysis proved out vital, as dealing with the issues required a more advanced methodological approach. The obtained results have enabled us clear insight into the available balance and contribute to a more effective continuation of the project.”