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To promote energy-saving potentials of the energy recovery unit under all-year conditions, a composite system combining pump-driven loop heat pipe with heat pump was firstly proposed, and the mathematical models were established. The operating characteristics of the composite system were studied in the whole year and compared with the traditional heat pump heat recovery system. The results show that the heating capacity of the composite system is in line with the heating load in winter. Compared with the traditional heat pump system, the composite system has higher energy efficiency ratio and lower deviation degree of temperature effectiveness in the whole year. The heat pump composite pump-driven loop heat pipe heat recovery system is generally superior to similar system reported in literatures, which indicates that it can replace heat pump system in buildings ventilation.

Based on the simulation results of the typical rural ultra-low energy building (ULEB) in five different climatic regions of China, three indicative technical parameters for paralleled-loop exhaust air heat pump (PEAHP) R&D which are nominal heating-cooling capacity, maximum required fresh air to return air ratio (MFRR) and system energy efficiency grades were calculated and summarized according to the demand of indoor thermal comforts by using statistic method. The nominal heating-cooling capacities were determined according to the peak loads, which are 6.84-2.01 kW, 5-2.96 kW, 3.9-4.6 kW, 3.08-5.02 kW, and 3.4-0.46 kW in the ULEB of Harbin, Beijing, Shanghai, Guangzhou, and Kunming, respectively. To ensure both thermal comforts and energy conservation, during the heating season, full fresh air supply is suggested in Beijing and the 1:0.5 MFRR is suggested in Harbin, Shanghai, Guangzhou, and Kunming. During the cooling season, the 1:5 MFRR is suggested in Shanghai and Guangzhou, the 1:3, 1:1.5, and 1:0.5 MFRR are suggested in Harbin, Beijing and Kunming, respectively. The PEAHP energy efficiency grades 1~5 are 7.92~11.7, 7.58~11.5, 7.5~11.35, 6.12~9.27, and 4.64~7.03 during the heating season of Harbin, Beijing, Shanghai, Guangzhou, and Kunming, respectively, and are 2.33~3.54, 3.93~5.96, 4.61~6.98, 4.62~6.99, and 2.04~3.1 for the cooling season, respectively.

The submerged plant species Carolina fanwort (Cabomba caroliniana) has become a dominant invasive aquatic plant in the Lake Taihu Basin (LTB) in China. Introduced species may escape their original specialist enemies and encounter fewer enemies in their new environment. They were assumed to have suffered less herbivory than native species as they are relatively unpalatable (the enemy release hypothesis [ERH]). The objective of this study was to compare the responses of C. caroliniana with those of co-occurring native species to herbivory from native herbivores. We conducted a mesocosm experiment to record the responses of C. caroliniana and two commonly co-occurring native submerged plant counterparts, water thyme (Hydrilla verticillata) and Eurasian watermilfoil (Myriophyllum spicatum), to herbivory by two native generalist gastropod snails, Radix swinhoei and Sinotaia quadrata. Plant morphological traits (total biomass, shoot/root [S/R] biomass ratio and relative growth rate [RGR]) and physiological traits (leaf total nonstructural carbohydrate [TNC], lignin, and cellulose) were recorded. The snail S. quadrata rarely influenced the plant traits of the three submerged plants. With the increasing numbers of R. swinhoei treatments, most of the plant traits of H. verticillata and M. spicatum changed, while those of C. caroliniana showed a relatively stable fluctuation. This result indicates that C. caroliniana is more resistant to herbivory by the snail R. swinhoei, which is consistent with the ERH hypothesis. This finding indicates that herbivorous snail species contributes to the invasion of C. caroliniana, which potentially alters the species composition of submerged plants in the plant community.

The improvement performance of refrigerating dehumidification system was theoretically discusses based on a dehumidification model. The influence of evaporator inlet wind speed, dry bulb temperature and relative humidity on dehumidification were analysed by the model. The results show that, when inlet air temperature and humidity were kept constant, the dehumidification capacity increased first and then decreased with increase of the wind speed. When the moisture content and the wind speed of the inlet air were kept constant, the dehumidification capacity gradually decreased with increase of the inlet air dry bulb temperature. The inlet air dry bulb temperature was between 21-36?C and the relative humidity was between 40% and 85%, the difference between the inlet air wet bulb temperature and the evaporation temperature at the optimum COP was about 10?C. There was a nearly linear relationship between the corresponding evaporation temperature at the optimal COP and the evaporation temperature with the maximum dehumidification capacity, compared with the test value, the error was less than 10%.

Three free-floating species that normally co-occur in the natural waters of southern China were studied—two globally introduced invasive species, Eichhornia crassipes and Pistia stratiotes, and a native counterpart, Hydrocharis dubia. The responses of the three species to different phosphorus and nitrogen levels were determined using root morphological parameters and topological indices. The results showed that P concentration levels had a significant effect on all of the root traits, except for the shoot/root ratio of P. stratiotes, whereas nitrogen had less impacts on the root traits. The root parameters consisting of lateral root number, root altitude, root length, total root length, root area, total root area, relative growth rate and root relative growth rate of E. crassipes were the highest among the three species. We found that the root branching of E. crassipes can be considered as a peculiar poly-herringbone branching system according to a new root topological structure model. The predominant root growth traits and root branching structure of E. crassipes and P. stratiotes help to explain their high absorption ability and fast growth, so the spread of these invasive species may be exacerbated as eutrophication intensifies in the future.

The submerged species Carolina fanwort (Cabomba caroliniana) has attracted considerable attention in Lake Taihu Basin (LTB), China. This species was widely used as a garden plant until 2016, when it was identified as invasive. In this study, we conducted a mesocosm experiment to compare the morphological traits, includingtotal dry mass, shoot/root (S/R) ratio, relative growth rate (RGR) and competition index log response ratio (ln RR), of C. caroliniana and two frequently co-occurring native submerged plants, water thyme (Hydrilla verticillata) and Eurasian watermilfoil (Myriophyllum spicatum). The results demonstrated that C. caroliniana did not show more advantageous traits (higher total dry mass, S/R ratio and RGR) or have a lower ln RR than H. verticillata or M. spicatum. We provide a counterexample to commonly accepted thought in which the successful invasion of invasive species may not be explained by outcompeting native plants. Other biotic or abiotic factors that determine the successful invasion of C. caroliniana must be studied further.

The indoor space of residential building is limited, especially in building retrofit, to improve the indoor space utilization and the performance of exhaust air heat recovery system, a novel dual-cylinder rotary compressor with independent suction and discharge ports was designed to drive an inverter parallel-loop exhaust air heat pump. Through the experiments and analyzing the parallel-loop exhaust air heat pump system working characteristics under variable compressor frequency and different fresh air volume flow rate, the optimized method is proposed and verified experimentally. Finally, the annual energy efficient operation plan was proposed, and the seasonal performance factor and seasonal average input power under this operation plan in three typical countries/organization were calculated. Results show that the system COP can be greatly improved by applying a mixed air supply method during winter. When the fresh-air-to-return-air ratio is 1:1 and the outdoor temperature is −5 °C, the system COP reached 10.18, which is the highest comparing with the related studies. In summer, the system COP is increased by increasing the ventilation volume flow rate. When the operation of the parallel-loop exhaust air heat pump system follows the energy efficient operation plan to ensure the temperature effectiveness over 100% and the outdoor working condition complies with GB 21455–2013, the heating season performance factor, heating season average input power, cooling season performance factor, and cooling season average input power are 7.22, 0.6909 kW, 2.83, and 0.8167 kW, respectively. The work would provide guidance for the development of exhaust air heat recovery system in residential building.