How to Source an Exhaust Waste Heat Recovery System

miratech-vaporphaseSourcing an exhaust waste heat recovery system can seem challenging at first, but we are here to help. Follow these steps to gather the necessary information and feel free to reach out to our office for assistance along the way.

First, what is an exhaust waste heat recovery system?

A waste heat recovery system (WHRS) is an essential component of a cogeneration or combined heat & power facility. These facilities rely on natural gas or diesel-driven engines to run continuously to generate power. During operation, as much as 30% of the fuel’s energy is transferred to the exhaust system. If not captured, this energy would be lost to the atmosphere. A WHRS is designed to recover the energy in the engine’s exhaust system, and use it to produce hot water or steam for use in the facility. With a larger share of the fuel’s energy being converted to useful assets, the facility can run more efficiently and cost effectively.

On to the nuts and bolts…

A WHRS is designed for a specific engine application, and also for the specific requirements of the cogeneration or CHP plant. There are a number of data points that are used to calculate the performance of the WHRS, and there are overall project/application details that guide the selection of a product for a specific project. Here are some of the items that we would ask our customers to provide:

Data Pertinent to the Engine(s):

  1. Engine Make/Model
  2. Rated Power (BHP)
  3. How many engines will be operating at the plant?
  4. What is the fuel type (diesel, natural gas, biogas, etc)? If gaseous, will it operate as a learn burn or rich burn?
  5. What is the engine’s full load exhaust flow rate, max exhaust gas temperature and max back-pressure allowance (this data can be found under the exhaust performance section in the engine’s technical data sheet)?

Data Pertinent to the WHRS Design:

  1. Will the WHRS be installed vertically or horizontally?
  2. What is the max pressure drop allowed through the WHRS?
  3. For hot water applications, what is the water flow rate, water inlet temperature and water-side pressure drop allowance?
  4. For steam applications, what is the feed water temperature, and the design steam pressure?

General Specifications:

  1. Will the WHRS be operating in conjunction with other equipment, such as an exhaust silencer, catalyst or SCR system?
  2. Are there specifications covering requirements for insulation, installation or construction materials?
  3. Are there mechanical plans showing requirements for piping elements such as bypass valves, support structures, etc?
What to expect from a vendor proposal?

A vendor’s proposal should consist of a commercial section and a technical section.

The commercial section will provide product descriptions along with pricing information, terms of sale and warranty details. The technical section will cover application details, the performance of the selected product, a detailed bill of materials and a complete description of the vendor’s scope of work. If the proposal includes on-site startup and commissioning assistance, you should be provided with specifics, as well as a checklist for “customer-furnished” items that must be in place to allow a successful installation.

Ready to get started?

We look forward to helping you with your next cogen or CHP project. Ready to get started? Call our office today!

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