Question on Microturbines

[ClydeMule]

I am looking for some info on microturbines:

1. I am trying to make hot water or steam from the hot exhaust. I think the term is a recuperator. Turbine size is 400kw. I know Capstone makes their own for the 60 kw system, but I need to come up with an mfg independent of the Turbine manufacturer. Any idears?

2. I see on turbine performance curves that the power output drops as the inlet air temp increases. But on the Capstone information, they use the term recuperator to refer to a heat exchanger that heats the incoming air using hot exhaust. They claim that this increases efficency.

These seem to be opposites; what is best cooling the intake air or heating it?

Thanks,

Clyde

 

[EdStainless]

As the inlet air temp increases the efficency goes up, but the power output goes down.
Hot air is less dense, so you get less oxygen, so you can burn less fuel, but you loose less heat to heating air.
Cool air is denser, you get more oxygen, you can burn more fuel and get more total power out of the same unit, but you efficency drops because you use a lot of heat warming up all of that cool air.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[davefitz]

The increase in the air entering the compressor first row of blades will decrease the amount of air that can flow thru the compressor, since the compressor is a constant volume device, and as the temp increases, the specific volume increases.To increase unit output on a hot day, one can use an inlet evap cooler, or inlet fogger spray ( using demin water), or an inlet chiller. For a Capstone, one option would be to use an absroption chiller, while the heat to power the absorption chiller would be from the turbine exhaust.

The use of the recuperator is to heat the compressor outlet air temp, prior to it entering the combustor. This reduces the amount of fuel needed to heat the air to TiT ( turbine inlet temp)and improves unit efficiency.

There are many vendors of heat rcovery boilers to match with the Capstone. Look at the Univ of Maryland engineering page- they have a gov't grant to develope cogen options for the capstone.

 

[GenB]

If you know exhaust gas amount and flow, you can size the boiler, hot-water or steam; for smaller units, heat exchanger design similar to a scotch boiler (firetube boilers) are common. for a used small boiler send info from steamequip.com
ER