[Gasification] Gasification or Pyrolysis + Absorption Chiller for Fruit

Oscar Jimenez Cabeza oscar at cubaenergia.cu
Fri Aug 15 09:02:47 CDT 2014


Dear Rolf,

Thanks for your note about COP´s value in absorption chillers. 
I am not really a cooling specialist. I am a chemical engineer who has been
always interested on thermodynamic, energy efficiency etc. 
When talking about absorption chillers there are two main technologies:

1. Lithium bromide chillers.
2. Ammonia chillers.

Usually the first one, as far as I know, are mainly used in air conditioning
systems. I remember reading articles, some years ago, about their
application in cooling class rooms in a college in United States.
The second one are mainly used for industrial cooling, in order to keep
vegetables and fruits at a proper temperature.
Actually when I made my estimates for Tom, I was mainly thinking on ammonia
chillers, based on what I mentioned above regarding what published
literature and thermodynamic texts states on this issue. 
Current state-of-the-art on this matter is something I am not wholly
updated, however anyone really interested may get a deeper insight should
there be enough time to spend on it.
Maybe re-estimating the figures, using a little bit less COP´s value, would
led to using more biomass to gasify in order to increase producer gas flow
to the chiller. The question is: Is there room for increasing producer gas
demand having the same level of cooling...????

Thanking you one more time.

Kindest regards.

Oscar.






-----Mensaje original-----
De: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] En
nombre de Energies Naturals C.B.
Enviado el: jueves, 14 de agosto de 2014 15:25
Para: gasification at lists.bioenergylists.org
Asunto: Re: [Gasification] Gasification or Pyrolysis + Absorption Chiller
for Fruit


Hallo Oscar,

the estimated COP of .6 is reported as normal for lithium bromide chillers,
but experiments in Spain some years ago led to minor COP s :

http://www.sciencedirect.com/science/article/pii/S1359431107002098

Abstract

Trials were conducted to determine the performance of a commercial
(Rotartica 045v) 4.5-kW air-cooled, single effect LiBr/H2O absorption
chiller for residential use. The experiments were run at La Poveda, Arganda
del Rey, Madrid, in August 2005. Three typical August days, with different
outdoor temperatures, were chosen for the study. The hot water inlet
temperature in the generator varied throughout the day from 80 to 107 °C.
Thermal demand was calculated, along with period energy balance and COP.
Variations in machine component temperatures were recorded and chilling
power and the daily COP calculated for each of the three days. The results
for the period as a whole showed that cooling power tended to decline with
rising outdoor dry bulb temperatures. At temperatures from 35 to 41.3 °C the
chilled water outlet temperature in the evaporator climbed to over 15 °C.
The average COP for the period, when auxiliary equipment was included into
the calculations, was 0.37.

But this refers to  a typical 100/40 °C situation. (Is that your
condensation figure in the tropics?)

I am by no means an absorbtion specialist, but I guess that with a different
configuration and the higher input temperatures
available from the gas flame (ammonium/water?) you can even chill down to
freezing temps at a reasonable COP.

I would be delighted to hear from our cooling specialists and learn what is
the state of the art.

Rolf


On Thu, 14 Aug 2014 10:26:30 -0700
"Tom Miles" <tmiles at trmiles.com> wrote:

> Oscar,
> 
>  
> 
> Thanks. This is a good start. 
> 
>  
> 
> Tom 
> 
>  
> 
> From: Gasification [mailto:gasification-bounces at lists.bioenergylists.org]
On
> Behalf Of Oscar Jimenez Cabeza
> Sent: Thursday, August 14, 2014 11:14 AM
> To: 'Discussion of biomass pyrolysis and gasification'
> Subject: Re: [Gasification] Gasification or Pyrolysis + Absorption Chiller
> for Fruit
> 
>  
> 
> Dear Tom,
> 
>  
> 
> I have always been interested in generating cold by using producer gas. I
> think it has been an issue which has unfortunately deserved little
> attention, when compared to power and heat production.
> 
> In order to answer your question,  I am sending my preliminary estimates
on
> the practical refrigeration capacity you are asking for.
> 
>  
> 
> 1.      Assuming 2.5 tpd of biomass to be gasified, it should deliver
> roughly 240 m3/h of producer gas.
> 
> 2.      Considering a COP value of 0.6 for the chiller.
> 
> 3.      LHV of the gas of 5000  kJ/m3.
> 
>  
> 
> My modest estimates of the refrigeration  capacity should be around 200
kW.
> 
>  
> 
> I hope those figures could be of help to you.
> 
>  
> 
> Kindest regards.
> 
>  
> 
> Oscar.
> 
>  
> 
>  
> 
>  
> 
> De: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] En
> nombre de Tom Miles
> Enviado el: jueves, 14 de agosto de 2014 12:08
> Para: 'Discussion of biomass pyrolysis and gasification'
> Asunto: [Gasification] Gasification or Pyrolysis + Absorption Chiller for
> Fruit
> 
>  
> 
> In the tropics there are needs for making char and cooling fruit. Has
anyone
> coupled a small pyrolyzer or gasifier up with a boiler and an absorption
> chiller? What sizes and capacities make sense? We're looking at a fuel
input
> of 2-3 tpd. How much char can I make and what practical refrigeration
> capacity can I generate? I am assuming that the chiller can get down to
> about 36 F (2 C). The cooler the better. 
> 
>  
> 
> Thanks
> 
>  
> 
> Tom
> 
> 
>   <http://correo.cubaenergia.cu/firma_correo.png> 
> 


-- 
Energies Naturals C.B. <energiesnaturals at gmx.de>

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