Yimo Luo

Technological and Higher Education Institute of Hong Kong · Building Services Engineering

Self-powered photovoltaic windows, which integrate photovoltaic with electrochromic devices, have attracted widespread attention of scholars since they can generate electricity in situ and reduce building energy consumption by modulating the transmitted solar radiation. However, previous studies mainly focused on the material development and perfor...

Thermochemical energy storage (TCES) with salt hydrates has attracted much attention due to its high energy storage density, low regeneration temperature, and long-term storage without energy loss. As a key component of the TCES system, the reactor has a major influence on the system performance. The traditional reactor has problems of non-uniform...

Vacuum-photovoltaic (VPV) glazing has attracted much attention due to its excellent thermal insulation performance and its ability to utilize solar energy. However, few simulation models have been established based on actual products and rarely have been validated by experiments. In this paper, a four-layer CdTe-based VPV glazing was developed and...

Comparative experimental studies on energy consumption and indoor thermal environment between convective air-conditioning terminals and radiant ceiling terminals, as well as the systematic scientific explanations for their differences, were rarely reported. In this study, comparative experiments have been carried out for convective air-conditioning...

In this study, the energy consumption and indoor thermal environment of a radiant ceiling heating and cooling system with three types of transparent building envelopes, namely, ordinary insulating glass (OIG), heat reflective insulating glass (HFIG) and triple silver low-e insulating glass (TSIG), were investigated and compared by experiment and si...

Liquid air energy storage (LAES) is increasingly popular for peak-load shifting of power grids, which includes air liquefaction at off-peak hours and power generation at peak hours. The standalone LAES system does not rely on external cold and heat sources, and hence is more favorable for applications. In the standalone LAES system, heat storage in...

Venetian blinds are widely used to improve the performance of window systems, while their energy-saving potentials vary with different materials. This paper aims to undertake a standardized evaluation of the annual energy-saving potential of venetian blinds in residential buildings, and identify the most influential parameters for design optimizati...

The falling film type liquid desiccant dehumidification cooling system and absorption refrigeration system are regarded as promising technologies due to their energy saving potential and utilization of low-grade energy. CFD (Computational Fluid Dynamics) technology has been continuously developed due to its advantages in analyzing the elaborate flo...

This paper tested the energy outputs of different types of PV modules and evaluated the accuracies of different simplistic PV module power prediction models. A test rig was developed in Hong Kong to assess the PV power outputs of ten PV modules. The solar radiation, ambient temperature and power generation are recorded. The evaluated models include...

Liquid air energy storage (LAES) has been regarded as a large-scale electrical storage technology. In this paper, we first investigate the performance of the current LAES (termed as a baseline LAES) over a far wider range of charging pressure (1 to 21 MPa). Our analyses show that the baseline LAES could achieve an electrical round trip efficiency (...

Liquid desiccant dehumidification is promising as it could be driven by renewable energy. In the present study, it newly investigated the dehumidification characteristics of KCOOH solution in an internally cooled dehumidifier. To select suitable concentration range, the vapor pressure of KCOOH solution with different solution concentration and temp...

Liquid air energy storage (LAES) is increasingly popular for decarbonizing the power network. At off-peak time, ambient air after purification is liquefied and stored; at peak time, the liquid air is discharged to generate power. One of the key challenges for the LAES system is the lower economic benefit as peak electricity is usually the only sour...

The potassium formate (KCOOH) solution is regarded as a promising alternative for the widely used salt solution in liquid desiccant dehumidification. However, few studies have been conducted to investigate the regeneration characteristics of KCOOH solution. In the present study, it firstly measured the vapor pressure of KCOOH solution with differen...

Further enhancing the dehumidification performance of liquid desiccant cooling system helps to get higher energy efficiency and better system performance. Previous studies mainly focused on experimental exploration of enhancement methods, such as surface modification and additives addition, which were greatly restricted by its huge investment and c...

Liquid Air Energy Storage (LAES) is one of the most promising energy storage technologies for achieving low carbon emissions. Our research shows that the LAES produces a considerable amount of excess heat that cannot be cost-effectively utilised in a standalone LAES system. On the other hand, the regasification of liquefied natural gas (LNG) often...

Compared with the extensive attention drawn by salt solutions, the promising potassium formate (KCOOH) solution which has smaller causticity and lower price receives little attention in the field of liquid desiccant cooling system (LDCS). Consequently, the present paper studied both the thermal properties and mass transfer performance of KCOOH solu...

The present study proposed a novel quasi-3D model for simultaneous simulation of heat and mass transfer process in a falling film dehumidifier with penetration mass transfer theory and CFD technology. Different from the existing 2D model, the new model took the shrinkage of falling film into consideration by introducing variable film wettability. B...

The present study firstly developed a new kind of mixed liquid desiccant for the purpose of causticity reduction on metal based regenerator. The formula of the mixed liquid desiccant is 25% LiCl + 39% hydroxyethyl urea + 36% water. Experimental results show that the causticity of the mixed solution is much less severe than that of conventional LiCl...

Desiccant enhanced evaporative cooling system is a sustainable air-conditioning (A/C) system which deals the latent load and sensible load separately by a dehumidifier and an evaporative cooler. A LDD-RIEC system consists of a liquid desiccant dehumidifier (LDD) and a regenerative indirect evaporative cooler (RIEC) were investigated. The LDD-RIEC s...

It was found that there were still very limited studies for the dynamic operation and transient performance of the dehumidifier. Besides, the coupling study of heat, mass and flow was not comprehensive and lots of assumption was made to start the simulation. Lack of accurate prediction, the guidelines of control system design and operation cannot b...

The present study intended to study the dehumidification performance of KCOOH solution both experimentally and numerically. The heat and mass transfer model for internal cooling dehumidifier was built. The influences of different parameters on dehumidification performance were identified by experiments. Results indicated that the air temperature an...

The present study studied the flow boiling heat transfer performance of a mini channel with offset fins experimentally. The hydraulic diameter for it is 1.59 mm with 9 offset rectangular channels. The influences of saturation pressure, mass flux and heat flux on heat transfer coefficient were investigated. The experimental results reveal that when...

The energy performances of c-Si PV windows and a-Si PV windows have been investigated comprehensively worldwide. However, CdTe thin film PV windows which are supposed to achieve better performance due to its higher efficiency are rarely studied. This study evaluated the energy performance of semi-transparent CdTe thin film PV window applying on com...

The liquid desiccant cooling system (LDCS) is a promising alternative for the conventional vapor compression system due to its high energy efficiency. To enhance the mass transfer between the regeneration air and liquid desiccant in the regenerator, the paper firstly introduced a kind of surfactant called polyvinyl pyrrolidone (PVP-K30) which was a...

The investigation showed that there were few researches about the real dynamic performance of solar assisted liquid desiccant air conditioning system with the unsteady term in the governing equations. Regarding the unsteady properties of the components, a novel dynamic model was developed for a solar assisted internally-cooled liquid desiccant air...

The traditional vapor compression cooling system (VCS) has been criticized for its heavy reliance on electricity consumption and limited control ability of humidity. Compared with the VCS, the liquid desiccant cooling system (LDCS) is more efficient by handling the sensible and latent load separately. The present study investigated the regeneration...

The desiccant enhanced evaporative cooling system is proposed as a promising energy-saving air-conditioning (A/C) scheme. It consists of hybrid liquid desiccant dehumidifier and indirect evaporative cooler. The hot and humid air is firstly dehumidified by liquid desiccant dehumidifier (LDD) and then sensibly cooled by regenerative indirect evaporat...

The falling film dehumidifier is a key component in the liquid desiccant cooling system (LDCS). However, the most commonly used metals, such as steel and aluminum, can hardly resist the erosion of liquid desiccant. It greatly limits the fabrication of compact dehumidifiers and hinders the promotion of LDCS. The present study introduced a novel fall...

Refrigerant subcooling could increase the refrigerating capacity and potentially improve the performance of refrigeration systems. In this paper, a novel subcooling method is experimentally studied for the first time in a hybrid vapor compression refrigeration system. In this system, condensation heat (around 40 °C) is used to drive an integrated s...

The hybrid liquid desiccant dehumidification and evaporative cooling system, short for LDD-EC system, is regarded as a promising energy-saving air-conditioning (A/C) scheme for hot and humid regions. Unlike most previous reported LDD-EC system based on traditional indirect evaporative cooler (IEC) and 100% fresh air system, the LDD-EC system with p...

The flow characteristics play great role in determining the heat and mass transfer performance of a falling film liquid desiccant dehumidifier. Even though there have been lots of studies reporting the flow behaviors in different devices and fields, the fundamental researches of the film flow characteristics in a liquid desiccant dehumidifier were...

Combined cooling, heating and power (CCHP) systems are regarded as efficient, reliable and environmentally friendly technologies for energy utilization. Besides, smart grid is an intelligent electricity delivering system brings benefits to utilities and consumers as well as improves the energy efficiency and reliability on the grid. The combination...

The indirect evaporative cooler (IEC) is a low-carbon device which cools the air with water evaporation. Its performances in dry regions have been investigated intensively. However, its application in hot and humid regions, where the IEC is used as a pre-cooling device in an air-conditioning system, is still at developing stage. The exhausted air f...

The dehumidifier of a liquid desiccant air conditioning system was the research object of present paper. A model was established on the basis of CFD. The interior heat and mass transfer processes were simulated with the model. Intensive analysis was conducted to investigate the influence of some factors, including the inlet desiccant temperature, d...

The indirect evaporative cooler (IEC), regarded as a low-carbon cooling device, was proposed as fresh air pre-cooling and heat recovery device in the air-conditioning system to break the region limitation of application in hot and humid areas. In this hybrid system, the exhausted air with low temperature and humidity from air-conditioned space is u...

The liquid desiccant air conditioning system is considered as a possible substitute of the traditional air conditioner mainly due to its characteristics of energy saving. The dehumidifier is a key component of the system therefore was chosen as the research object. It was found the present models conducted the simulation with lots of assumptions, e...

To reduce the chiller energy consumption in a central air-conditioning system, a heat exchanger, acting as an air cooler, can be installed before an air handling unit to pre-cool the fresh air by recovering cooling capacity from exhaust air. However, studies on evaluating the performances of air cooler under condensation condition are limited. Ther...

The dynamic characteristics of solution film flow with counter-current air flow, especially the two phase contact area, are important for the optimal design and operation of LDD (liquid desiccant dehumidifier). However, the unsteady interfacial information, including the interfacial pressure, velocity and film thickness, is hardly to be examined ac...

The indirect evaporative cooler (IEC), regarded as a low-carbon cooling device, was proposed as fresh air pre-cooling and heat recovery device in the air-conditioning system to break the region limitation of application in hot and humid areas. In this hybrid system, the exhausted air with low temperature and humidity from air-conditioned space is u...

In a hybrid cooling system, an indirect evaporative cooling (IEC) unit is installed before an air handling unit to pre-cool the incoming fresh air, in order to reduce the energy consumption of the air-conditioning system. When the system is applied in humid regions, as the dew point temperature of the fresh air is higher, condensation will probably...

Evaporative cooling (EC) is an energy efficient and environmental friendly technology which uses water evaporation to absorb the heat from surroundings and produce cooling air. EC has limited application cases in hot and humid regions because of the relatively low cooling capacity. In recent years, the study on hybrid EC and traditional mechanical...

Te liquid flow has great impact on the heat and mass transfer behavior in the liquid desiccant dehumidifier. However, there is limited investigation on the liquid flow conditions in the dehumidifier. Thus, the paper investigated the liquid flow behavior on a flat and corrugate plate, respectively. The minimum liquid flow rate for wetting the whole...

The optimal design and operation of a liquid desiccant dehumidifier needs the understanding of the flow mechanism. However, the study in this aspect is still limited. In the present work, a model has been established on the basis of computational fluent dynamics (CFD) software. With the model, the counter-current gas-liquid flow process is evaluate...

The experimental studies of fin-tube type internally-cooled dehumidifiers are still limited until now. In the present paper, the performance of a cross-flow internally-cooled dehumidifier is studied by both of experiment and simulation. The dehumidifier is made up of fin-tube heat exchangers with high corrosion resistance. Compared with the dehumid...

A new simulation model for simultaneous heat and mass transfer combined with the volume of fluid (VOF) surface tracking method has been developed for a simplified liquid desiccant dehumidifier. The model has taken the effect of the velocity field on the heat and mass transfer process into consideration. The desiccant flow has been simulated accordi...

The corrosion problem of traditional liquid desiccants hinders the development of solar liquid desiccant air conditioning system. Ionic liquids (ILs) could be a possible substitute because of their low corrosion to metals. According to the characteristic of cation and anion, two ILs 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4) and 1,3-...

Some ionic liquids have dehumidification capacity and are non-corrosive to metals. Based on the Finite Difference Method, the heat and moisture transfer model of the counter-flow dehumidifier was established. Using this model, the dehumidification capacity of one kind of ionic liquids 1-Ethyl-3-methylimidazolium Tetrafluoroborate ([EMIM]BF4) and tr...