In today’s environment of high gaseous fuel prices, gas engine based Combined Heat and Power installations also called Cogeneration or CHP represent an attractive solution to investors to provide reliable heat and power to their industry or production while maximizing their return on investment.
Combined Heat & Power (CHP or Cogeneration) – is one of the most popular energy-saving technologies. It is the simultaneous and sequential use of power and heat from the same fuel source. When generating electricity, a large amount of heat is produced as a by-product.
In traditional power generation methods this is wasted, but a CHP system recycles this heat. In other words, heat recovered from generation is used for heating or cooling, typically with an absorption chiller. This reduces the transmission and distribution losses that occur when fuel is burned, increasing the efficiency of the system. Use of heat for both heating and cooling is known as Tri-generation.
Cogeneration installations in Greenhouses are particularly interesting since the CO2 from the gas engine exhaust is used in the greenhouse in addition to heat and power and will help accelerate the plants growth.
CHP schemes are mainly used by the industrial, commercial and some public sectors – mainly those needing a great deal of heat such as hospitals, universities, leisure centers, offices and retailers. Those industries can be divided in three categories:
- The ones with intensive electric applications: hospitals, offices, shopping malls, industrial processes, logistic centers, etc. Here, the primary purpose for installation is electric power. CHP operates when electricity is required and utilizes load balancing radiators - exhaust circuit bypass.
- The ones with requiring heat and power equally: cement plants, chemical processes, food processing. In this case, both heat and electric power have equal value. Here, CHP are much more complex systems, which require radiators and thermal accumulators.
- And the ones with intensive heat applications: greenhouses, district heating, central steam plants. These applications' primary purpose for installation is heat-related. Such system operates when heat is required and utilizes thermal accumulators-direct connection, which can be hot water or steam circuits.
Advantages of cogeneration plants versus traditional energy generation systems:
- Possibility to generate heat an power simultaneously.
- Possibility to utilize renewable energy sources.
- Reliable energy source - there is no dependance on local utilities
- Significant reduction of CO2 emission into atmosphere, etc.
Although good qaulity CHP may not be as 'clean' as renewable energy,nevertheless as it is usually a gas-fired product, it is cleaner than many other fossil fuels. It is efficient because it combines electricity with wasted heat, and there is usually 3:1 improvement in the emission of CO2 into the atmosphere.
Traditional renewable energy sources are oversubscribed, making CHP an excellent and viable alternative. With the benefit of a high quality and secure energy source system on site, companies can reduce their dependency on the national grid for power. While a typical output of a gas engine is about 42% of total fuel gas energetic input, more energy can be recovered from an engine by recovering the heat from the aftercooler, the engine jacket water, the lube oil cooling water, as well as the exhaus gases. This allows as per below schematic to recover around 90% of the total inputted energy.
With the medium used to recover the heat is generally hot water, steam can as well be generated and used to feed absorbtion chillers or other steam processes. Most commonly, the hot water is used as process water for heating purposes and hence eliminates the need for extra boilers and contributes to increase the overall plant efficiency.
Combined heat and power is significantly more efficient than utilizing power from the grid alone. By capturing heat from production of power most CHP facilities are able to save considerable money on fuel.
CHP is becoming more economical and widely accepted as oil and gas prices increase and the world desires to reduce greenhouse gas emissions. Governments are also providing increased incentives for sustainable power resources.