Assessment of dehumidification performance of non-corrosive desiccant in hybrid liquid desiccant-vapour compression system

ABSTRACT

Air-conditioning (AC) systems, which operate on traditional vapor compression refrigeration (VCR) systems, consume a substantial proportion of the world’s electricity consumed by the building industry. In the scope of decreasing greenhouse gas emissions, energy consumption, heating, ventilation, and air conditioning industries have focused on finding alternatives to electrically operated VCR systems. A combination of a liquid desiccant dehumidification system (LDDS) with a VCR system has been recommended as a superior substitute in warm and moist climates. The focus of this research article is to design and fabricate a small-scale 5 kW hybrid LDDS system by integrating the distinct technologies mentioned above. Additionally, data collected on the vapor pressure of potassium formate (KCOOH) at various solution concentrations and temperatures is being collected to assist in encouraging research and determine the optimal concentration range. In this study, experimental analysis and comparison of dehumidification performance was conducted between two desiccants by analyzing the effects of input variables ($m_a$, $T_d$, and ${\omega }_s$) on the output response ($\mathrm{\Delta }\omega$, $Q_{deh}$, and $CO{P}_h$). The results showed that the solution with a 69.92% KCOOH concentration had nearly the same vapor pressure as a solution with a 35% LiCl concentration. Moreover, it was revealed that the lowest values of $m_a$ and $T_d$ and the highest value of ${\omega }_s$ yield maximum values of the output responses. At the same combination of input variables, the KCOOH desiccant has a much higher hybrid system coefficient of performance than the LiCl desiccant.

KEYWORDS:

• hybrid system
• liquid desiccant
• vapor pressure measurement
• dehumidification
• coefficient of performance

Nomenclature

ACAir-conditioning

COPCoefficient of performance

$CO{P}_h$Coefficient of performance of hybrid system

$CO{P}_{hp}$Coefficient of performance of heat pump

$CO{P}_{sys}$Coefficient of performance of system

CaCl₂Calcium chloride

$c_{pa}$Isobaric specific heat (kJ/kg.K)

DOEDesign of experiments

D1Concentration of KCOOH solution

D2Concentration of LiCl solution

$h_{fg}$Latent heat of evaporation (kJ/kg)

$\mathrm{\Delta }{h}_{abs}$Enthalpy of absorption (kJ/kg)

$\mathrm{\Delta }{h}_{dil}$Enthalpy of dilution (kJ/kg)

hpHeat pump

IAQindoor air quality

KCOOHPotassium formate

LDDSLiquid desiccant dehumidification system

LDACLiquid desiccant air conditioning

LiClLithium chloride

LiBrLithium bromide

LHLLatent heat load

MgCl₂Magnesium chloride

MARDMean absolute relative deviation

MRRMoisture removal rate

TRTons of refrigeration

$T$Temperature (${ }^{\circ }C)$

$T_a$Temperature of air (${(}^{\circ }C)$)

VCRVapor compression refrigeration

Greek letters

$\mathrm{\Delta }\omega$Specific humidity change (kg of water vapor/kg of dry air)

${\omega }_s$Specific humidity of air (kg of water vapor/kg of dry air)

Disclosure statement

No potential conflict of interest was reported by the author(s).