Solar-desiccant air-conditioning systems - Solar Energy Sciences and Engineering Applications - page 528

climate. Further solar desiccant with chiller is feasible in terms of economic and energy
point of view in the warm-humid climate in which energy saving of 50% is possible.
Mavroudaki et al. (2002) presented a numerical investigation with regard to the appli-
cation of single-stage desiccant air-conditioning system in European cities. The system
is applicable in some parts of southern Europe as long as latent load is not high; this
is due to the high regeneration temperature requirement for high relative humidity air.
The system is feasible in most of central Europe. Atlantic and inland regions of south-
ern Europe appear to be much more suitable to this technology than Mediterranean
costal regions.
Smith et al. (1994) investigated the application of solar-powered solid desiccant
air-conditioning system in residential buildings in the United States through transient
system simulation (TRNSYS) simulation. The study focused on the Pittsburg (Mas-
sachusetts), Macon (Georgia) and Albuquere (New Mexico). It showed that building
cooling demand was met, and that solar energy is suited to the operation of desiccant
AC in the southwest of the US, with 72.7% of energy from solar. In the southeast of the
county, 18.0% of desiccant air-conditioning was provided by solar energy. Casa and
Schmitz (2005) investigated the application of borehole heat exchanger in desiccant
air-conditioning with a gas engine (Figure 16.5.1). The system, installed in a demon-
stration building, saved 70% of energy for desiccant with a borehole heat exchanger. In
the case of desiccant with chiller, it can save up to 30%. Cler (1992), investigating the
possibility of applying desiccant dehumidification in military facilities, showed that it
is recommended when additional cooling capacity is needed in existing HVAC systems.
Also, for higher quantities of outdoor air make-up, a desiccant-based system is ideal
for this type of application. In new construction, desiccant dehumidification equip-
ment should be considered. This would reduce the size of chiller and electric energy
demand. In addition, when designing new desiccant air-conditioning systems, desic-
cant regeneration from vapour compression, solar energy, cogeneration and others
should be considered in the early phase of design.
Halliday et al. (2003) looked at the feasibility of applying solar desiccant air-
conditioning systems in the UK. This study showed that the solid desiccant with solar
power is feasible for application in buildings as long as the system is applied in a proper
manner. Henning et al. (2007) investigated the application of desiccant air-conditioning
system in a tri-generation system (power + heating and cooling). This used a vapour
compression chiller and silica gel desiccant with the electricity to drive the chiller
coming from combined cooling, heating and power CCHP, while the regeneration of
the desiccant wheel was powered by waste heat from CCHP. An electric saving of more
than 30% was made compared to the conventional air handling system.
Enteria et al. (2012) conducted a numerical investigation of the solar-powered
desiccant air-conditioning system in East Asia (Northeast Asia and Southeast Asia).
The system ventilation rate increased from the temperate Northeast Asia to tropical
Southeast Asia. The solar desiccanr air-conditioning system is applicable under East
Asian climatic conditions as long as the proper specifications are applied, such as the
size of the flat-plate collector, inclination of the collector plate, thermal storage tank
volume and the required air flow rates going to the building. In addition, an alternative
desiccant air-conditioning system in which air cooling can be done independently can
reduce the air flow rate requirement, as a pure desiccant air-conditioning system cannot
support a lower supply air temperature.