Heat exchangers in series

[kmpillai]

I would like to heat the air from 480K to 1200K using Gas turbine exhaust with supplimentary fuel firing.Heat capacity(i.e. mass* specific heat) is almost same in both the air and flue gas side.
Cold side: Tin = 480 K Tout = 1200K pure air
Hot side: Tin is arrived from effctiveness definition working medium flue gas.

Case I with the single heat exchanger of effctiveness 85%

Case II with 2 heat exchanger of each effctiveness 85% seriously connected.

Whether Case I and II will give the same performance? Hot flue gas temperature required at heat exchanger inlet is same for both the cases ? if not why and where I can find more details? I will be very thankful if somebody is replied.

 

[easternequipment]

Dear Sir,

In both cases of using either 1 or 2 heat exchangers, the total quantum of heat input required for the system would be similar. ( With two heat exchangers, the losses would be slightly higher due to inherent system losses.)

Please clarify the following :

1.Air volume to be heated.
2.Heating from 480 K to 1200 K.
3.Flue gas volume and inlet temperature / and outlet permissible.

Inlet temperature of flue gases, mixed with products of combustion from another source to increase mixed flue temperature / capacity, can be same for both methods.

We manufacture waste heat recovery recuperators and air preheaters, and can help you in this matter. Our contact details are given below.

Vikas Agrawal.
easternequipment@vsnl.com

 

[kmpillai]

Mr Vikas Agrawal Thank you for your response and I am giving the following details.
1. air mass flow rate = 4.79 kg /s
flue gas mass flow rate = 4.61 kg /s
2. air inlet temp = 480 K
air outlet temp = 1200 K
3. Gas side:
flue gas inlet temp = as low as possible (Theoretically 1200K for a 100% effectiveness hx)
flue gas exit temp = as low as possible.

I expecting your early response. Thank you very much.