[TRNSYS-users] energy rate -Storage tanks

[Michaël Kummert]

Florian,

> o.k. my solar system is connected over an heat exhanger to the " Hot 
> side entrance" of Type 4e. the average water draw(type14b) is connected 
> to the "cold side in". so this storage tank is connected to a second 
> tank(type 60d) directly without a pipe. the " ... to load"(type4e) to 
> the inlet1, and the " ...to heat source "(type 4e) to the solar system.
> type 4e gives out an output "energy rate to load" and type 60d
> an output "energy supplied from inlet1".. so i thought this enrgy rates 
> should be nearly the same
> (all are direct connections)

Type 4's "energy rate to load" is the difference of enthalpy flows 
entering and leaving the tank on the load-side:
QLoad = mdot*Cp*(Tout-Tin)
Tout is the " temperature to load" (usually top node)
Tin is the "Cold-side temperature"  (usually mains temperature)

On the other hand, Type 60's "Energy supplied by inlet 1" is 
mdot*Cp*Tin1, where Tin1 is Tout from Type 4.

So QLoad(Type 4) should not be equal to Qin1 (Type 60). Since we can 
reasonably expect Tin(Type 4) to be positive, QLoad(Type 4) will always 
be slightly smaller than Qin1(Type 60), as you mention in your first email.

Kind regards,

Michaël Kummert

-- 
_________________________________________________________

Michaël Kummert

Solar Energy Laboratory - University of Wisconsin-Madison
1303 Engr Res Bldg, 1500 Engineering Drive
Madison, WI 53706

Tel: +1 (608) 263-1589
Fax: +1 (608) 262-8464
E-mail: kummert at engr.wisc.edu

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