Humidity Ratio Research Articles

Simulation of the Effect of Air Humidity Ratio in the Drying Room on the Rate of Material Evaporation in Vacuum Freeze Drying

Simulation of the Effect of Air Humidity Ratio in the Drying Room on the Rate of Material Evaporation in Vacuum Freeze Drying

Investigation of purge angle on the air inhomogeneity reduction and energy efficiency improvement of the desiccant wheel dehumidification system

ABSTRACT The rotary desiccant wheel dehumidification system has been extensively applied to achieve deep dehumidification in the modern environment with low humidity ratio. The effect of mixing destruction caused by the temperature and humidity inhomogeneity on the thermodynamic performance of the desiccant wheel deep dehumidification (DWDD) system has not been thoroughly illustrated. This research aims to reduce the mixing destruction and improve the overall energy efficiency of the DWDD system. Numerical analyses were carried out to investigate the mixing destruction characteristics of the deep dehumidification process. The results revealed that the mixing exergy destruction gradually becomes a prominent factor as regeneration temperature and humidity ratio increase under deep dehumidification, and there is a significant temperature and humidity ratio gradient in the transition angles from the regeneration side to the process side. The purge angle is regulated to reduce the average temperature and humidity ratio on the process side and lower the air inhomogeneity. The exergy efficiency of the desiccant wheel can be improved from 44.8% to 73.9% at the regeneration humidity ratio of 20 g/kg under the effective purge angle of 30°, indicating a considerable enhancement of exergy efficiency under the effective purge angle at a high regeneration humidity ratio.

Performance predication of a solar assisted desiccant air conditioning system using radial basis function neural network: An integrated machine learning approach

In this Paper solar desiccant air conditioning system integrated with cross flow Maisotsenko cycle (M-cycle) indirect evaporative cooler is used to investigate the performance of whole system in different range of parameters. Solar evacuated tube electric heater is used to supply the regeneration temperature to the desiccant wheel, whereas, Desiccant Wheel (DW) and M-cycle is used to handle latent load and sensible load separately. Major contribution of this research is to predict system level performance parameters of a Solar Assisted Desiccant Air Conditioning (Sol-DAC) system using Radial Basis Function Neural Network (RBF-NN) under real transient experimental inlet conditions. Nine parameters are mainly considered as input parameters to train the RBF-NN model, which are, supply Air temperature at the process side of desiccant wheel, supply air humidity ratio at process side of the desiccant wheel, outlet temperature from the desiccant wheel at process side, outlet humidity ratio from the desiccant wheel at process side, regeneration temperature at regeneration side of the DW, outlet temperature from the heat recovery wheel at process side, outlet humidity ratio out from the Heat Recovery Wheel (HRW) at process side, temperature before heat recovery wheel regeneration side of the system, humidity ratio before heat recovery wheel regeneration side of the system. Four parameters are considered as the output of the RBF-NN model, namely: output temperature, output humidity, Cooling Capacity (CC), and Coefficient of Performance (COP). The results of the RBF-NN model shows that the best Mean Squared Error (MSE) and Regression coefficient (R) for outlet temperature prediction are 0.00998279 and 0.99832 when regeneration temperature is 70 °C and inlet humidity at 18 g/kg. Best MSE and R for predication of outlet humidity are 0.0102932 and 0.99485 when the regeneration temperature is 70 °C and inlet humidity at 16 g/kg. Best MSE and R for predication of COP are 0.0106691 and 0.9981 when the regeneration temperature is 70 °C and inlet humidity 12 g/kg. Best MSE and R for predication of CC are 0.0144943 and 0.99711 when the regeneration temperature is 70 °C and inlet humidity 14 g/kg. Experimental and predicted performance parameters were in close agreement and showed minimal deviation. Investigations of predicted results revealed that trained RBF-NN model was capable of predicting the trend of output result under the varying input condition.

Direct/indirect optimal use of shallow geothermal energy in floor radiant cooling system coupled with air-handling system

Shallow geothermal energy is used as the cold source of floor radiant cooling systems (RFCSs). A physical simulation test bench was built to study the cooling and dehumidification characteristics of an RFCS to evaluate its feasibility. Three operation modes involving direct-supply chilled water, direct-supply chilled-water coupling air-handling system (AHS), and indirect cascade utilization were evaluated. Results showed that the room could be cooled rapidly in the direct-supply chilled-water mode. When the direct-supply chilled-water temperature was lower than 16 °C, condensation occurred on the floor surface. The AHS effectively avoided condensation, and the maximum humidity ratio difference between the air inlet and outlet was 13.61 g/kg. However, the temperature difference between the chilled water and the floor surface was reduced. Under the cascade utilization mode, the cooling efficiency of the system improved, and the indoor temperature and relative humidity were maintained at 20.6–28.1 °C and 57.0–76.1 %, respectively. This study provides valuable insights into the direct application of geothermal energy in RFCSs.

Global estimation of range resolved thermodynamic profiles from micropulse differential absorption lidar

We demonstrate thermodynamic profile estimation with data obtained using the MicroPulse DIAL such that the retrieval is entirely self contained. The only external input is surface meteorological variables obtained from a weather station installed on the instrument. The estimator provides products of temperature, absolute humidity and backscatter ratio such that cross dependencies between the lidar data products and raw observations are accounted for and the final products are self consistent. The method described here is applied to a combined oxygen DIAL, potassium HSRL, water vapor DIAL system operating at two pairs of wavelengths (nominally centered at 770 and 828 nm). We perform regularized maximum likelihood estimation through the Poisson Total Variation technique to suppress noise and improve the range of the observations. A comparison to 119 radiosondes indicates that this new processing method produces improved temperature retrievals, reducing total errors to less than 2 K below 3 km altitude and extending the maximum altitude of temperature retrievals to 5 km with less than 3 K error. The results of this work definitively demonstrates the potential for measuring temperature through the oxygen DIAL technique and furthermore that this can be accomplished with low-power semiconductor-based lidar sensors.

Research on Relative Humidity and Energy Savings for Air-Conditioned Spaces without Humidity Control When Adopting Air-to-Air Total Heat Exchangers in Winter

In view of the problem that the exchange effectiveness is calculated according to a fixed value or only considering the influence of outdoor air parameters when analyzing the suitability of total heat recovery for plate heat recovery equipment in air-conditioned spaces without humidity control, the indoor humidity calculation model and moisture balance equation were established in this research to predict relative indoor humidity. Moreover, the relationship between total heat recovery, effective heat recovery, and the reduction in outdoor air heating load was analyzed using a psychrometric chart of the outdoor air treatment process. Referring to the standard for weather data of building energy efficiency in the Ningbo region, 6 typical days were taken as the calculation conditions. The moisture balance differential equation was solved using MATLAB software to obtain numerical solutions for the hourly indoor air humidity ratio, relative humidity, exchange effectiveness, and effective heat recovery when adopting an air-to-air total heat exchanger in an air-conditioned room of an office, classroom, or commercial building in the winter. The results indicate that, under the calculation conditions, the relative indoor humidity of commercial buildings is relatively high, making it unsuitable for a total heat exchanger. The relative humidity of indoor air in offices and classrooms can be maintained above 30%, and the total exchange effectiveness of a total heat exchanger is between 45% and 100%. The effective total heat recovery was calculated as sensible heat recovery under most calculation conditions.

Study on indoor air temperature and moisture behaviour in historical churches

Increased indoor air humidity in cultural heritage buildings in the Baltic States region results in the deterioration of cultural heritage values. Existing norms, standards, and research do not specify the necessary conservational microclimate indoor air parameter limits. Two main types of historical cultural heritage building constructions exist based on enclosing structures – wood and masonry, with various heating strategies and usage intensities. This study complements previous research on the microclimate of Krimulda Church and compiles measurements of three additional Latvian churches: Turaida Church, Riga Jesus Church, and Liepaja St. Trinity Cathedral. Microclimate measurements were conducted in two wood and two masonry churches. Humidity ratio and moisture excess calculations were derived from the measurement data. Results indicate that in certain cases, the moisture excess threshold of 6 g/m3 and indoor air humidity ratio threshold of 15,6 g/kg are exceeded, posing a significant risk of condensation. Moisture evaporation levels from masonry church constructions were identified. The study reveals conservational microclimate indoor air parameter limits for various types of churches in the Baltic States climatic region.

Theoretical and experimental research on the performance of new building environment control systems based on cooling dehumidification under positive pressure

A significant amount of energy consumed by building environment control systems is used for dehumidification. However, the conventional cooling dehumidification method is energy-intensive as the low required dew-point temperature and reheating. In this paper, two different new building environment control systems based on cooling dehumidification under positive pressure are proposed, which can realize dehumidification with a natural cooling source at ambient temperature. The cooling dehumidification model under positive pressure is proposed and verified by experiments, and the errors are within ± 4.16 %. Influences of pressure ratio and cooling source temperature on system performances are analyzed by simulation. The result shows that proposed systems can achieve the dehumidified air with a humidity ratio of 8.18 g/kgDA and a temperature of 20℃, and the dehumidification energy efficiency of new systems can achieve 6.11 kg/kWh. At a cooling source temperature of 18 °C and pressure ratio of 1.6, the total dehumidification rate of the system can reach 19.49 g/s. Reheating in front of the expander can reduce the detrimental dehumidification proportion to 0 %. The coefficient of performance (COP) of the new system can reach 6.26, which is superior to other dehumidification methods.

Theoretical and experimental study of the effect of biomass based organic packing wettability on the LDDS and its life cycle analysis

Present study aimed at the fabrication of a counter flow dehumidifier unit using biomass-based organic materials like coconut coir and wood shave as packing alternatives. The wettability of these packings is evaluated by arranging them structurally and their influence on the dehumidification performance has been experimentally studied. A prediction-based mathematical model is constructed to simulate the performance of biomass packing materials. Theoretical and experimental results were very close, with an average deviation of 8.33% for wood shaving and 5.79% for coconut coir packings. Overall, this unit gave the rate of moisture removal (MRR), dehumidification effectiveness (DE), coefficient of mass transfer (MTC) and specific humidity ratio equal to 0.70 g/s, 76%, 37 kg/m2-s and 0.78 respectively. A packing life study and its influence on dehumidification performance is checked. After the third week of continuous usage, results revealed that air contamination CO2, TVOC, and HCHO levels increased by 14.60%, 34.48%, and 38.46%, and the moisture removal rate decreased by 29%, for wood shaving packing. After the third week, the performance deteriorated since the packing fragments became brittle due to the salt interaction. This fibre breakage affected the wettability significantly.

Assessment of the Possibility of Excluding Secondary Heating of the Inflow During the Warm Period in Modern Climatic Conditions

The subject of the study is the dependence on the required indoor air temperature and the accepted inflow temperature for a minimum heat and humidity ratio in the room, in which secondary heating of inflow can be excluded. The purpose of the study is to obtain an analytical expression of this dependence, which allows an engineering assessment of the possibility of eliminating secondary heating in the process of designing air conditioning systems without the use of graphical constructions. The objective of the study is to represent an adequate flow processing scheme on the I–d diagram, identify the main factors affecting the minimum heat and humidity ratio in the room and obtain the necessary numerical coefficients in formulas linking the desired and initial parameters. Research results. An analytical dependence is obtained that allows calculating the minimum possible value of the heat and humidity ratio in a room in which secondary heating is not required, and only cooling of the inflow with drying in a surface air cooler is sufficient if it has a bypass channel. The presentation is illustrated with numerical and graphical examples.

Identification of Convective Boundary Layer Depth over the Great Lakes Region Using Aircraft Observations: A Comparison of Various Methods

Abstract This study evaluates the methods of identifying the height zi of the top of the convective boundary layer (CBL) during winter (December and January) over the Great Lakes and nearby land areas using observations taken by the University of Wyoming King Air research aircraft during the Lake-Induced Convection Experiment (1997/98) and Ontario Winter Lake-effect Systems (2013/14) field campaigns. Since CBLs facilitate vertical mixing near the surface, the most direct measurement of zi is that above which the vertical velocity turbulent fluctuations are weak or absent. Thus, we use zi from the turbulence method as the “reference value” to which zi from other methods, based on bulk Richardson number (Rib), liquid water content, and vertical gradients of potential temperature, relative humidity, and water vapor mixing ratio, are compared. The potential temperature gradient method using a threshold value of 0.015 K m−1 for soundings over land and 0.011 K m−1 for soundings over lake provided the estimates of zi that are most consistent with the turbulence method. The Rib threshold-based method, commonly used in numerical simulation studies, underestimated zi. Analyzing the methods’ performance on the averaging window zavg we recommend using zavg = 20 or 50 m for zi estimations for lake-effect boundary layers. The present dataset consists of both cloudy and cloud-free boundary layers, some having decoupled boundary layers above the inversion top. Because cases of decoupled boundary layers appear to be formed by nearby synoptic storms, we recommend use of the more general term, elevated mixed layers. Significance Statement The depth zi of the convective atmospheric boundary layer (CBL) strongly influences precipitation rates during lake-effect snowstorms (LES). However, various zi approximation methods produce significantly different results. This study utilizes extensive concurrently collected observations by project aircraft during two LES field studies [Lake-Induced Convection Experiment (Lake-ICE) and OWLeS] to assess how zi from common estimation methods compare with “reference” zi derived from turbulent fluctuations, a direct measure of CBL mixing. For soundings taken both over land and lake; with cloudy or cloud-free conditions, potential temperature gradient (PTG) methods provided the best agreement with the reference zi. A method commonly employed in numerical simulations performed relatively poorly. Interestingly, the PTG method worked equally well for “coupled” and elevated decoupled CBLs, commonly associated with nearby cyclones.

Study of water-side free cooling technology for power lithium battery plant

Power lithium battery production process needs to consume a lot of energy. In this paper, an energy consumption analysis of a representative company was conducted, the energy consumption of the facilities that provide support for the process is higher than the energy consumption of the process equipment itself, which greatly affects the cost of battery manufacturing. Air-conditioning system as the most important energy-consuming system of the facilities, accounting for 25% to 45% of the total electricity consumption. The energy consumption of the cooling source system dominates, even in winter its energy consumption can reach 14% of the total energy consumption. On this basis, this paper analyzes the chilled-water-use characteristics of the air-conditioning terminal in winter through theoretical analysis, the chilled water temperature is therefore optimized according to the real-time outdoor humidity. The chilled water temperature is linearly increased after the humidity ratio fall below 7.5g/kg(a), reaching a maximum value of 12.1°C at 6g/kg(a). In addition, the cooling tower free cooling technology based on the optimized chilled water temperature is innovatively proposed to fully explore the energy-saving potential of the technology to achieve the energy saving of the cooling source system. TRNSYS simulation results show that after optimizing the chilled water temperature, the time period for cooling tower individual cooling under winter operating condition is extended by 60%, and cooling source system energy saving rate can reach 49.0% and the cost saving rate 48.0%, both of which are higher than 15% compared to the un-optimized chilled water temperature.

Performance evaluation of a passive air conditioning module integrating radiative sky cooling and indirect evaporative cooling

Amidst escalating global warming challenges, the demand for sustainable, carbon-free cooling technologies in buildings has become pressing. While radiative cooling (RC) and indirect evaporative cooling (IEC) are carbon–neutral, their efficacy is constrained by a limited cooling capacity. This study introduces an innovative passive air conditioning module that integrates RC and IEC to boost efficiency. The RC-IEC module unifies the air-conditioning process in both the RC and dry channels of the IEC unit, ensuring air cooling with a constant humidity ratio. A portion of the IEC dry channel outlet air is redirected to the wet channel to augment the efficiency of the IEC process. The outlet air from the wet channel is directed to the secondary RC air channel for cold energy recovery instead of being directly exhausted. The developed mathematical model, validated with experimental data, demonstrates that the RC-IEC system lowers the supply air temperature by 0.88 °C compared to the IEC-only system. This corresponds to an 11.91 % and 9.94 % improvement in dew-point effectiveness and cooling energy gain, respectively. A parametric study indicates the system's suitability for hot, arid climates, with optimal performance at a wet channel air mass fraction of 0.31. The analysis of the annual cooling performance of the RC-IEC system across diverse climates, spanning from Athens to Singapore, spotlights Dubai's system as the most efficient, achieving a remarkable annual gain of 1081.09 MJ. The study emphasizes the need for tailored strategies, such as advanced air dehumidification technologies, to optimize cooling in humid regions like Singapore.

The impact of wettability on the performance of a two row wavy fin and tube liquid desiccant system for dehumidification and regeneration

This study investigates the challenge of enhancing wettability in falling film type dehumidifiers/regenerators, a crucial factor in optimizing the performance of building air conditioning systems. The emergence of Severe Acute Respiratory Syndrome (SARS) has underscored the need for improved indoor air quality (IAQ) and energy efficiency. This research specifically addresses the suboptimal wettability issue in fin and tube liquid desiccant systems, which is essential for efficient dehumidification and regeneration processes. The experimental setup employed a cross-flow configuration within the heat exchanger elements, where the flow of ionic liquid intersected with horizontal airflow through cooling and heating coils. By systematically adjusting the wettability on the heat exchanger surfaces, the study examined its impact on relative humidity and dry bulb temperature at the system's inlet and outlet. The results indicate that the wetting fraction on fin and tube surfaces significantly influences the delta humidity ratio of air. In the dehumidification phase, for instance, the delta air humidity ratios varied between 9.4 and 9.7 g/kg with corresponding wetting ratio values ranging from 0.47 to 0.5. Similarly, during regeneration, delta air humidity ratios fluctuated from 9.08 g/kg to 9.6 g/kg, with wetting fractions between 0.47 and 0.5. In conclusion, this study offers in-depth insights into the impact of wettability on the efficiency of fin and tube liquid desiccant systems. These findings have implications for enhancing IAQ and energy efficiency in building air conditioning, particularly in tropical regions like Indonesia.

Theoretical Study on Falling Film Fin-Tube Dehumidifier Integrated With an Evaporative Cooler

Abstract The current work presents the theoretical analysis of a falling film fin-tube dehumidifier integrated with an evaporative cooler using CaCl2 as a liquid desiccant. In a fin-tube dehumidifier, the fins are provided outside the tubes to sustain the solution temperature during dehumidification. The evaporative cooler is compiled with a dehumidifier to provide cool air over the fins for maintaining the solution and air temperature. The theoretical model examines the heat and mass transfer between the air and the solution, which are moving in a counterflow direction inside the tubes. The study first presents the validation of the theoretical model with the experimental findings. The maximum disparity between theoretical and experimental results for moisture reduction with solution volume flowrate is found to be ±6.2%, whereas it is discovered to be ±13.8% for moisture reduction with airflow rate. The paper then discusses the air and solution parameters variation along the tube height and the impact of air and solution inlet parameters on system performance. The findings indicate that the variation in outlet air humidity ratio with tube height from 0 to 1 m is observed highest, 0.0264 kg/kg d. a. to 0.0233 kg/kg d. a., for a solution volume flowrate of 12.5 LPM and an airflow rate of 0.05 kg/s. The maximum variation in moisture effectiveness with tube height is observed from 0.0045 to 0.292 at 5 LPM solution volume flowrate and 0.05 kg/s airflow rate.

Ecological and Faunistic Analysis of Lumbricidae Species Composition of Natural Biogeocenoses and Man-made Territories

Earthworms make up the bulk of the soil mesofauna and play an important role in the transformation of organic matter, the formation of the pedosphere, the regulation of the flows of matter, energy and information in ecosystems. In this research, we have studied the species composition of earthworms in urban and suburban ecosystems of the foothills of the Trans Ili-Alatau. As a result of the work, 11 species of the Lumbricidae family of the Oligochaeta class were discovered. 6 species out of them have been discovered in our Republic: Aporrectodea rosea, Lumbricus rubellus, Lumbricus castaneus, Octolasion lacteum, Dendrobaena octaedra and Aporrectodea caliginosa are widespread. The genus Lumbricus is the most common in terms of the number of individuals in the studied territories. Significant differences have been established in the species composition of earthworms in technogenic and natural biogeocenoses. The lumbricides are the absolute dominants in two ecosystems. Along with the species composition of earthworms, seasonal dynamics were also studied, it was found that their maximum activity is observed at the most favorable ratio of temperature and humidity.

Changes in Intergranular Air Properties and Chemical Parameters of Short-term Stored Bulk Shelled Corn with Slightly High Moisture Content

Objective: This study is to determine the main parameters influencing the storage of shelled corn with slightly high moisture content (MC) so that its quality can be maintained. Methods: The intergranular air properties and chemical changes was determined in 4,169 tonnes of shelled corn bulk with an average MC of 15.3% and a height of 5m, which was stored for 90 days in a large warehouse in Shandong Province, China, from winter to early spring. The intergranular air property parameters were calculated with self-compiled software. Results: Fans were used to achieve temperature-equalizing aeration at a low rate (5.87m3/h/t) after warehousing, which decreased the bulk temperature from 6.8 to 4.7℃. Afterwards, with the increase in ambient temperature, the surface-layer grain temperature increased drastically, while that of the bottom layer increased slowly and those of the middle layers increased even more slowly. The minimum and mean cumulative dry-bulb, wet-bulb and dew-point temperatures (DPT) increased in the order of middle layer˂ bottom layer˂ surface layer. Free fatty acid content, kernel breakage percentage, water adsorption rate, gelatinization enthalpy, peak enthalpy, and fatty acid profiles (C16:0, C18:0, C18:3n3, C20:0 and C20:1) were significantly related to the cumulative intergranular air properties of grain bulk. Conclusion: The above physio-chemical parameters were significantly influenced by the minimum and mean cumulative values of relative humidity, Humidity ratio and DPT in the bulk, and can be used to evaluate the quality of shelled corn with slightly high MC during short-term storage.

Using Pearson correlation coefficient as a performance indicator in the compensation algorithm of asynchronous temperature-humidity sensor pair

Artificial Intelligence (AI) based control algorithms for heating, ventilation, and air conditioning (HVAC) equipment have been gradually applied to improve building energy efficiency. Nevertheless, a reliable dataset is certainly a cornerstone for any meaningful AI training. Unfortunately, significant errors exist on humidity records due to asynchronous humidity and temperature sensor time constants, which need to be better compensated. This study aims to verify the general applicability of the previously proposed compensation algorithm and discover a new method to determine essential parameters for the algorithm without lab testing, which makes it possible to apply the compensation algorithm to on-duty sensor pairs. Experiment results from newly tested sensor pairs are found comparable to the previous study's outcome, which confirms the algorithm's general applicability. Meanwhile, the newly proposed performance indicator – the Pearson correlation coefficient (PCC) of humidity ratio and temperature – results in a 64–97 % error reduction on the tested sensor pairs. Despite not being as steady as the original lab method, the PCC proved a possible alternative method worth further investigation due to its accessibility.

On-site measurement and optimization of energy efficiency of the cascading desiccant wheel deep dehumidification systems in the lithium-ion battery manufacturing factory

The desiccant wheel deep dehumidification system in the lithium-ion battery manufacturing factory is significantly energy intensive, which substantially treats the process air from the ambient to the supply air state with a dew point temperature below −20 °C. On-site measurements were conducted in this study to investigate the actual performance of the deep dehumidification systems. The air treatment process and energy consumption during the operation were continuously monitored. The results reveal that the coefficient of performance of the dehumidification process of the systems ranges from 0.54 to 0.63 under basic winter conditions and ranges from 1.15 to 1.25 under basic summer conditions. The deep dehumidification processes of the systems are divided into multiple stages, and with the deepening of the process air humidity ratio from above 6 g/kg to below 0.3 g/kg, the partial energy efficiency of the treatment stages decreases. The efficient operational strategies are further elaborated for the improvement of the deep dehumidification system, including the proper match between the dehumidification gradient and the dehumidification stages, and the appropriate use of outlet process air with low humidity ratio as the regeneration air. The energy consumption of the cascading desiccant wheel dehumidification system can be reduced by lowering the cooling temperature of the cooling coil to undertake more latent load in the preliminary dehumidification stage. The effect of the bypass air state as the regeneration air is revealed, and the energy efficiency of the system is enhanced by up to 32 % by applying appropriate bypass air. This study offers guidance for the future design of the cascading desiccant wheel deep dehumidification system in similar applications.

Experimental Research on Effects of Combustion Air Humidification on Energy and Environment Performance of a Gas Boiler

Abstract To increase the waste heat recovery (WHR) efficiency of gas boiler and decrease NOx emissions, a flue gas total heat recovery (FGTHR) system integrating direct contact heat exchanger (DCHE) and combustion air humidification (CAH) is put forward. The experimental bench and technical and economic analysis models are set up to simulate and evaluate the WHR performance and NOx emissions in various operation situations. The results show that when the air humidity ratio elevates from 3 g/kgdry air to 60 g/kgdry air, the dew point temperature increases by 7.9 °C. When the flue gas temperature approaches the dew point temperature, the rate of improvement of the FGTHR system's total heat efficiency notably rises. With spray water (SW) flowrate and temperature of 0.075 kg/s and 45 °C, the WHR efficiency relatively increases by up to 8.4%. The maximum sensible and latent heat can be recovered by 4468 w and 3774 w, respectively. The flue gas temperature can be reduced to 46.55 °C, and the average NOx concentration is 39.6 mg/m3. Compared with the non-humidified condition, the NOx and CO2 emissions relative reduction of the FGTHR system are 61.2% and 8.7%. The payback period of FGTHR system is 2 years. Through simulation, it can be concluded that the decrease in exhaust flue gas temperature and velocity, as well as the increase in exhaust flue gas humidity, has a negative impact on the diffusion of NOx in the atmosphere.