Cold Zone Of China Research Articles

A probabilistic model for residential community heating load calculation based on occupancy patterns

Ensuring precise prediction of community heating loads is crucial for optimizing the performance of district heating systems. However, the currently prevalent methods, like the simultaneous usage coefficient method and the area index method (AIM), which heavily rely on practical engineering experience, may not be suitable for ultra-low energy residential buildings (UERBs). Applying these methods to UERBs may result in overcapacity of the heating system, which increases energy consumption and costs. This study aims to enhance the accuracy of heating load calculations for UERB communities. A probabilistic model for heating load calculation was proposed, considering the “part time, part space” spatiotemporal distribution characteristics of residents. Typical occupancy patterns in cold zones of China were identified through questionnaire surveys and K-means cluster analysis, and typical models of UERBs were established, with both the building models and survey data validated. The residential building energy model (RBEM) was applied to a case community in Dalian, analyzing the impact of occupancy patterns on heating loads. The results indicate that the RBEM method increased the system's heating load factor by 6.9 % and reduced its design capacity by 32.9 % compared to the AIM. The proposed method might guide the development of management strategies in the energy planning stage of district energy systems.

A Long-Duration Glacier Change Analysis for the Urumqi River Valley, a Representative Region of Central Asia

The increasing global warming trend has resulted in the mass loss of most glaciers. The Urumqi Vally, located in the dry and cold zone of China, and its widely dispersed glaciers are significant to the regional ecological environment, oasis economic development, and industrial and agricultural production. This is representative of glaciers in Middle Asia and represents one of the world’s longest observed time series of glaciers, beginning in 1959. The Urumqi Headwater Glacier No. 1 (UHG-1) has a dominant presence in the World Glacier Monitoring Service (WGMS). This paper supplies a comprehensive analysis of past studies and future modeling of glacier changes in the Urumqi Valley. It has received insufficient attention in the past, and the mass balance of UHG-1 was used to verify that the geodetic results and the OGGM model simulation results are convincing. The main conclusions are: The area of 48.68 ± 4.59 km2 delineated by 150 glaciers in 1958 decreased to 21.61 ± 0.27 km2 delineated by 108 glaciers in 2022, with a reduction of 0.47 ± 0.04 km2·a−1 (0.96% a−1 in 1958–2022). The glacier mass balance by geodesy is −0.69 ± 0.11 m w.e.a−1 in 2000–2022, which is just deviating from the measured result (−0.66 m w.e.a−1), but the geodetic result in this paper can be enough to reflect the glacier changes (−0.65 ± 0.11 m w.e.a−1) of the URB in 2000–2022. The future loss rate of area and volume will undergo a rapid and then decelerating process, with the fastest and slowest inflection points occurring around 2035 and 2070, respectively. High temperatures and large precipitation in summer accelerate glacier loss, and the corresponding lag period of glacier change to climate is about 2–3 years.

Effects of inorganic mulching on soil hydrothermal environment and tomato characters in the presence of unheated greenhouse cultivation

The present study was conducted by cultivating tomato (Solanum lycopersicum ‘Provence’) using varied inorganic mulching to investigate soil hydrothermal environment and tomato characters under unheated greenhouse cultivation in the cold zone of China. A total of 6 different treatments were adopted: no mulching (control), white film mulching (white film), black film mulching (black film), the white film with hole mulching (white hole), the black film with hole mulching (black hole), and snake skin bag mulching (snake skin). Inorganic mulching treatment significantly improved soil temperature and moisture, water use efficiency, tomato yield, and reduced soil water consumption. There was no significant difference observed in the variation of daily mean soil temperature between different mulching treatments, and the variation was in the range of 1.95–2.20 °C, which was significantly lower compared with the control (3.42 °C). The daily mean soil moisture varied significantly after different mulching treatments, with the highest level achieved by snake skin (23.37%), followed by black hole (22.55%), white hole (22.08%), white film (21.48%), black film (20.12%), and control (18.78%) in descending order. According to the research results, plastic-hole mulching, which include white hole and black hole treatments, performed better in maintaining soil temperature and moisture.

Effects of organic mulching on moisture and temperature of soil in greenhouse production of tomato under unheated greenhouse cultivation in the cold zone of China.

In the cold zone of China, winter is cold and long and has a short duration of sunshine. Unheated earthen-wall solar greenhouses are used for tomato production in winter in this region. This was an experimental investigation of different organic mulching materials (newspaper, bran, and grass) on the soil temperature, soil moisture, tomato yield, fruit quality, and water use efficiency. Organic mulching variously improved soil temperature, soil moisture, water use efficiency, and tomato yield, which is very important for greenhouse winter cultivation in this cold zone. Organic mulching regulated the soil temperature, with daily soil temperature ranges of bran, newspaper, and grass treatments being 1.6, 1.9, and 2.1°C lower than for bare land, respectively. Compared to bare land, newspaper mulching had little effect on soil temperature and fruit quality, but increased soil moisture (14.1%) and water use efficiency (WUE: WUEb, 31.3%; WUEy, 30.6%), and greatly increased yield (81.8%) and biomass (82.7%); bran mulching greatly increased soil temperature, moisture (16%), and WUE (WUEb, 60.1%; WUEy, 44.3%) and increased biomass (30.2%) and yield (17.3%); grass mulching greatly increased soil temperature and moisture (20.9%) and increased biomass (17.9%), yield (11.2%), and WUE (WUEb, 20.5%; WUEy, 13.6%). In addition, organic mulching had a good water retention effect on soil layer above 30 cm. The total soil water consumption during tomato growth was in the following order: newspaper (103 mm) > bare (74 mm) > grass (73 mm) > bran (60 mm). Soil water consumption mainly occurred in the 0- to 10-cm soil layers.

Effects of climate change on long-term building heating performance of medium-deep borehole heat exchanger coupled heat pump

The medium-deep borehole heat exchanger (MDBHE) coupled heat pump (HP) is a promising building heating solution for carbon reduction. Existing studies claim that the MDBHE-HP suffers a bottleneck challenge of long-term heating performance degradation because of the heating extraction attenuation of the MDBHE, which largely hinders the practical applications of the MDBHE-HP. This study innovatively proposes and justifies that climate change positively compromises the heating extraction attenuation of the MDBHE and significantly improves the long-term building heating performance of the MDBHE-HP. Climate change reduces the building heating load, which mitigates the heating extraction attenuation of the MDBHE, thereby reducing the unmet level of the building heating load. The mitigated heating extraction attenuation enhances the coefficient of performance of the MDBHE-HP, thereby reducing the heating energy consumption. Case studies of 30-year operation in the severe cold and cold zones of China with different geological conditions show that while the heating extraction attenuation of the MDBHE increases the heating energy consumption by 5.0% – 8.7%, climate change reduces the heating energy consumption by 9.2% – 17.0%. Moreover, climate change reduces the unmet level of the building heating load by 70.5% – 100%. Therefore, the positive effects of climate change on the long-term building heating performance of MDBHE-HP should be considered, which contributes to promoting the practical applications of the MDBHE-HP for low-carbon building heating.

Energy consumption and indoor environment evaluation of large irregular commercial green building in Dalian, China

Commercial buildings, especially large irregular commercial buildings with complex space and dense occupation, have high energy consumption and carbon emissions. Moreover, the actual operating performance differs significantly from its design, in terms of energy conservation and carbon emissions. This study selected an irregular large-scale green commercial building in Dalian, a coastal city in the cold zone of China. The running energy consumption and indoor physical environment were investigated and analyzed, and a satisfaction survey was conducted using the Post-occupancy evaluation (POE) methods. The promotion strategies of holistic design were proposed by comparing the operational building performance with the design target. The research shows that the energy consumption of the building was 68.02 kWh/m2, which failed to meet the standard requirements. The carbon emission was 74.76 kgCO2/m2. Less than 10 % of humidity in summer fell in the expected range, and the lowest value of PM2.5 concentration in winter was 28.3 %. The score of indoor environmental quality and service satisfaction was low. This paper identifies the problems and analyzes the differences between the operation stage and design phase. It provides recommendations and guidelines for optimizing the carbon emission and indoor environment based on the performance improvement of building operational conditions.

Thermal adaptation of different set point temperature modes and energy saving potential in split air-conditioned office buildings during summer

The Chinese government issued a regulation that the cooling set point temperature (SPT) in office buildings cannot be lower than 26 °C. Therefore, SPTs were divided into different modes: SPT≥26 °C and SPT<26 °C. To study the human thermal adaptation of different SPT modes and determine the comfort and energy saving of the policy, a field test and subjective questionnaires were conducted in 21 split air-conditioned (SAC) office buildings during the warm season in the cold zone of China. We measured the environmental parameters and subjects' skin temperatures, and the subjective thermal responses were also investigated. The results showed that 45% of the air conditioner SPTs were less than 26 °C. In the high SPT mode, people's physiological adaptability to the warm environment was stronger, and subjects were more active in reducing clothes and increasing air velocity to improve thermal discomfort. Because the two modes had similar thermal histories and the same perceptual control, in the same SET ranges, no significant differences were found in thermal sensation, acceptability and comfort between the two SPT modes. The effects of long-term indoor thermal history on human thermal adaptation varied with the thermal exposure type, mode and intensity. From the analysis of thermal adaptation, the rationality of the policy was fully proved, and it was determined that SAC office buildings could save 26.4–35.2% of power energy consumption by reasonably increasing SPT in the cold zone. The results can enrich the thermal adaptation theory and provide a theoretical basis for the government's energy-saving policies in SAC office buildings.

The applicability and energy consumption of a parallel-loop exhaust air heat pump for environment control in ultra-low energy building

• A novel inverter driven dual-cylinder rotary compressor was used. • The energy efficient working mode was proposed. • The system can well satisfy the requirements of building. A novel dual-cylinder rotary compressor was designed to improve the indoor space utilization, and it was used to drive a parallel-loop exhaust air heat pump (PEAHP) which integrates the functions of heating, cooling, ventilation and heat recovery. The operation characteristics of the system in different compressor frequencies and different fresh-air-to-return-air ratios (FRRs) were studied and analyzed experimentally. Through the simulation of the ultra-low energy buildings (ULEBs) in 12 cold zone cities, the hourly (8760 h) building thermal loads in the whole year are calculated. On the basis of the matching of the hourly system working characteristics and the thermal loads of ULEB, the energy efficient working strategy is proposed. Finally, the applicability and energy consumption of the PEAHP system applying in ULEBs were analyzed. The results show that, the system heating/cooling capacity and COP can be considerably improved by increasing return air volume flow rate. In winter, under the working condition of 50 Hz-FRR 1:1, the peak heating capacity and COP are 8.94 kW and 9.63, respectively, which are 77.38% and 64.05% higher than those when FRR is 1:0. In summer, when the outdoor temperature ranges from 26 °C to 40 °C, the system temperature effectiveness is higher than 1 in all working modes. The PEAHP system has great applicability for ULEBs in cold zone of China during winter, and the system can meet the year-round use demands of the ULEBs in Taiyuan, Dalian, Lanzhou, Yinchuan and Lhasa, with the unsatisfied heating/cooling time ratio of 1.61%, 0.09%, 0.006%, 2.45% and 0.02%, respectively.

An experimental study of the summer and winter thermal performance of an opaque ventilated facade in cold zone of China

As a promising envelope technology for energy saving, opaque ventilated facades (OVFs) have spread to various climates and regions. Nevertheless, few reports have been published on their application in a typical continental climate zone with hot summers and cold winters, especially in China. Within the framework of a Chinese nationally funded project, comparative experiments were conducted on two full-scale test rigs to assess the thermal and energy performance of an OVF in cold zone of China. By comparing the conductive heat flux across the internal wall, the facade design features, including joint opening ratio, external cladding color, air vents openness and cavity width, showed substantial impacts on the thermal behaviors of the OVFs. It was highlighted that the surface solar radiation control features most affected the summer performance, while those restricting the cavity ventilation dominated winter. By integrating the optimal solutions for each design feature, the summer- and winter-optimal OVF configurations were proposed, bringing 11.4% and 6.5% energy use reductions compared to a conventional monolithic facade, respectively. Moreover, the daytime energy-saving effects of the OVFs were proved more significant, meaning that they were more suitable for daytime use buildings. However, considering the highly differed structures for these optimal OVFs, an integrated configuration was further qualitatively proposed through a normalized analysis of all tested facades, aiming for the optimal annual performance with minimal construction and operation complexities. These results provide general guidelines for designing performance-optimized OVFs while demonstrating a climatically representative sample from cold zone of China.

Field investigation on the thermal environment and thermal comfort in shopping malls in the cold zone of China

Reducing the energy consumption of large shopping malls is beneficial to achieving China's dual carbon goals. This study aims to explore the thermal comfort demands of occupants and provide guidance for the energy-efficient design of the indoor thermal environment in shopping malls. We selected nine typical large shopping malls in the cold area of China as the research object and carried out a year-long field study, which involved the survey of physical environment parameters and subjective questionnaires. 3175 valid data sets were obtained in all seasons. The study results found that the indoor thermal environment suffers from overheating in winter and overcooling in summer. The neutral Top is 21.3 °C, 25.4 °C, 19.0 °C, and 17.4 °C in spring, summer, autumn, and winter, respectively. The upper limit of the 80% temperature acceptability range in summer was 27.5 °C. The 80% acceptability range in winter (16.4–23.2 °C) is wider than GB 50736 standard, which can be appropriately relaxed for the HVAC temperature setting in the mall. Apparent vertical thermal stratification exists in the malls and significantly affects the occupants' thermal comfort. Compared to the PMV model, the adaptive model was more applicable for thermal environment evaluation of shopping malls in transition season and summer. This study proposes indoor temperature settings under the premise of meeting human thermal comfort, which provides references for the design and operation of shopping malls in cold-climate zones.

Indoor environmental quality and energy consumption real-time assessment: A field measurement of a nearly zero-energy building in cold region of China

The paper presents a two-year field measurement and assessment of a nearly zero-energy Building in cold zones of China. These parameters of indoor environment quality (IEQ) and electricity consumption for HVAC are recorded. According to the measurement data, the most of indoor temperature was controlled in the range of 23 °C ~ 26 °C and relative humidity (RH) mainly fluctuates within the range of 30% ~ 60%. The concentrations of carbon dioxide (CO2) and particulate matter (PM2.5) are lower than the relevant standard requirements in most of the time. The average electricity consumption for HVAC was 33.05kWh/(m2·a) and the heating and cooling demands could be reduced by 55.2% and 54.0%, respectively, compared with existing buildings. In general, the NZEB can provide indoor comfortable thermal environment and indoor air quality with less energy demand, but the overheating problem in summer and effect of occupant behavior should be especially paid attention during operation. Overall, the experience from the actual operation of NZEBs will help China to reach its goals of reducing carbon emissions and addressing climate change through realizing the energy-saving potential of NZEBs.

Multiple Pathways Regulation of Greenery on Thermal Comfort in Residential Communities in the Cold Zone of China

Multiple Pathways Regulation of Greenery on Thermal Comfort in Residential Communities in the Cold Zone of China

Dynamic simulation of thermal load and energy efficiency in poultry buildings in the cold zone of China

Understanding the dynamic heating and cooling load of poultry houses enables more precise environmental housing control; however, there is a lack of efficient tools for evaluating and predicting these loads. The objectives of this study were to develop and validate a toolkit to simulate the hourly building load throughout a year, simulate the base room temperature, and investigate the thermal performance of a commercial poultry house in Beijing. Various infiltrating air volumetric flow rates (0.2, 0.6, 1.0, and 2.0 air changes per hour) and total ventilation rates under three mortality levels (5.0%, 10.0%, and 15.0%) were used for the simulation to compare the annual heating and cooling load (AHL and ACL). The correlations between measured and simulated data were 0.99 for indoor air temperature and 0.90 for relative humidity. Based on the simulation results, the base room temperature was −9.2 to 42.2 °C throughout the year. The recommended temperature was met only 38.80% of the year, indicating that extra energy must be consumed to maintain a suitable temperature all year. Air inlets (windows and doors) were altered to meet Chinese energy efficiency standards, which decreased the maximum AHL and ACL by approximately 11.10% and 4.81%, respectively. When the tightness of envelope construction was adjusted from “loose” to “medium” and from “loose” to “tight”, the maximum AHL decreased by 15.45% and 19.86% and the maximum ACL decreased by 4.45% and 5.72%, respectively. Decreasing the ventilation rate reduced the hourly cooling and heating load from 12.51 to 50.04 KW and 3.75–15.01 KW, respectively, due to different mortality rates when the air temperature difference was 5.0 °C and 20.0 °C. The proposed simulation toolkit is an effective and accurate tool for evaluating and predicting dynamic building loads for poultry houses. Hourly dynamic thermal simulations throughout the year can accurately determine potential problems in housing systems and lead to appropriate energy-saving strategies.

Dynamic Simulation and Operating Characteristics of Ground-Coupled Heat Pump with Solar Seasonal Heat Storage System

A hybrid ground-coupled heat pump (GCHP) is an efficient and sustainable technology for space heating and cooling. A demonstration house equipped with GCHP with a solar seasonal heat storage (SSHS) system had been built in Harbin, a severe cold zone of China. A dynamic simulation model was built for the house and GCHP with the SSHS system using TRNSYS. The model used a newly developed vertical ground heat exchanger (VGHE) module which considered coupled heat and moisture transfer (CHMT) in ground with variable soil properties (VSPs) and phase change of soil moisture (PCSM). In the simulation, a large amount of computing is consumed for VSP and PCSM, while the computing amount for moisture transfer is small. The model with the new VGHE module produced better simulated results, compared with the field data. So, CHMT-VSP-PCSM affects the performance of VGHE and system to some extent, especially CHMT. Hourly variation laws of temperatures and energy parameters were analyzed, and different characteristics were showed up at different operating stages in heating and cooling seasons for both long and short terms. The GCHP with the SSHS system can meet the heating and cooling demands of the house in general. In cooling season, adjusting the ratio of the two groups of VGHE for heat storage and cooling will increase the utilization efficiency of VGHE and make the soil temperature more balanced.

Applicability of different energy efficiency calculation methods of residential buildings in severe cold and cold zones of China

With the accelerated development of dynamic energy consumption simulation software, the accuracy and feasibility of steady-state calculation method for energy efficiency designs of residential buildings in severe cold and cold zones should be investigated. A six-story residential building model as a case study is introduced to be calculated and simulated by steady-state calculation method elaborated in ‘Design standard for energy efficiency of residential buildings in severe cold and cold zones’ and dynamic energy consumption simulation of EnergyPlus software respectively, in order to compare and analyze the differences between these two methods in five typical cities of China (Xi’an, Lhasa, Xining, Harbin and Hailar). The findings indicate that the index of heat loss of building obtained from both methods is different to typical cities with varied difference ratios. Especially in cities of high altitude, strong radiation and greater diurnal range, namely Lhasa and Xining, the difference ratio is as high as 43.83% and 16.63%. Thus, dynamic energy consumption simulation should be used for counting residential building energy efficiency instead of steady-state calculation method in above mentioned zones by analyzing main factors concerning the differences.

Numerical and experimental research of cold storage for a novel expanded perlite-based shape-stabilized phase change material wallboard used in building

Phase change material (PCM) used in building can enhance the thermal inertia of building and improve the indoor thermal comfort. A novel shape-stabilized phase change material wallboard (PCMW), in which paraffin was as the PCM and expanded perlite (EP) was the supporting material, has been prepared through a horizontal vacuum absorption rotate roller (HVARR) in this study. Its melting point and freezing point were measured to be 27.60 °C and 23.56 °C, respectively, and the melting and freezing latent heats reached to be 67.13 J/g and 67.06 J/g, respectively. PCMW was experimentally and numerically studied to analyze the thermal performance. The experimental result in 5 days, which was a demonstration in a container subject to weather conditions typical for the north China, showed that PCMW used in the building can maximally reduce the indoor temperature of 2.53 K. For the numerical study, based on the equivalent heat capacity method, a one-dimensional heat transfer model of PCMW was developed and combined with TRNSYS. This model was validated by the experimental data, and the numerical data agreed well with the experiment data. Under the summer condition, the numerical study of PCMW used in a typical office building during two months showed PCMW can averagely reduce the temperature of 9.22 K in the building operation time (7:00–18:00). Besides, according to the numerical model, an optimal configuration of PCMW in the cold zone of China has been obtained. The studied method provides a comprehensive guide to the PCMW design and application.

Optimal Intermittent Regulation of Tubes-embedded Building Envelope Cooling System

This paper purposed to study the optimization of intermittent control schemes of tubes-embedded envelope cooling system, based on a typical office building in cold zones of China. TRNSYS was used to build building and system model and simulate the dynamic indoor thermal environment of different intermittent control schemes. The effects on indoor thermal environment and system energy consumption of different cooling time length and different cooling time distribution were analyzed. Basing on the simulation results, the optimal intermittent regulation basing on the trade-offs between two objectives including energy efficiency and thermal comfort was established. The results show that the eight-hour cooling period is optimal for typical office building in Xi’an city with typical envelope structure and buried pipe parameters under the condition of using supply water with 19 ℃. However, increasing the length of cooling time can reduce peak load. The results also show that frequent starts and stops of pump under the same length cooling time can increase the cooling capacity obtained by room.

Experimental on a novel solar energy heating system for residential buildings in cold zone of China

The traditional Chinese Kang system is a kind of ancient domestic heating system, which is still widely used in nearly 85% of rural homes in northern china. However, this system has the disadvantages of heating the room by burning biomaterials directly, which will cause serious environmental pollution. Inspired by the Chinese Kang system, a novel contacting heating sys-tem was proposed in this research. Solar-assisted air source heat pump was employed as heating source for the system. By change the temperature of supplied water, this system can be served as a heating bed, a heating chair or a radiant heating terminal for residential buildings. In order to verify the feasibility of the system, an experimental system has been set up and a series of experimental tests were carried out. The experimental results shown that this system can satisfy all the residents’ heating demands in residential buildings. Moreover, the proportion of the solar energy to the total energy consumption of the system even greater than 60%. These results may lead to the development of designing and distributing the solar energy for building heating during winter.

An experimental study of all-season operation strategy for a respiration-type double-layer glass curtain wall system in cold zone of China

Double-skin facade (DSF), as one of modern architecture envelopes, is beautiful and transparent. However, as transparent building envelope, double-skin facade has shortcomings in thermal performance, such as direct sunlight in summer. In order to overcome these drawbacks, a year-round optimum operation strategy of respiration-type double-layer glass curtain wall, which is one kind of double-skin facade with natural air circulation and blind system, has been researched by an experimental way in an office building. The optimum operation strategies that included changing air circulation and adjusting blind sun shading angle and installation position has been studied through comparative experiments in two identical rooms of the office building. For a year-round using in the cold zone of China, the related experiments were conducted in three stages: summer, winter and transition season. It was found that the optimum operation strategies in three seasons were different, but all of them have obtained well results. First of all, with the sun shading of blinds and the air external circulation, temperatures of air flow duct and room were decreased in summer. And then, with blinds removing, the indoor room can be warmed up by “greenhouse effect” created by respiration-type double-layer glass curtain wall for winter using. At last, in transition season, respiration-type double-layer glass curtain wall has increased the indoor thermal comfort and supplied fresh air.

Correlation analysis of building plane and energy consumption of high-rise office building in cold zone of China

With the rapid growth of high-rise office buildings in China, the huge energy consumption of these buildings has become a concern recently. While much research is focused on the HVAC system efficiency, there is little study on the association between building plane and energy consumption from the perspective of passive building design priority. In this study, 8 cases of typical high-rise office building plane in 6 categories are established in the city of Beijing, which is located in cold climate zone of China, and the annual dynamic load and energy consumption are calculated using the Design Builder software. The correlation between plane and energy consumption was studied based on the analysis of several key related factors. They are functional area ratio, shape coefficient, plane functional depth, traffic space arrangement, large atrium and natural lighting. The results show that, compared to total floor area, energy consumption per functional area is a more applicable index to evaluate building plane efficiency and energy consumption level across different design schemes. Influences of shape coefficient on energy consumption are mainly in envelope load. Compared with building depth, functional depth has a higher correlation with energy consumption. It is positively correlated with lighting energy consumption, and negatively correlated with envelope load. Traffic space arrangement mainly affects lighting, solar heat gain and envelope load, while its influences on total energy consumption need to be considered comprehensively. Our simulation results show that the differences of energy consumption across all the cases can be up to 17%, and a linear plane with a traffic space arranged in the north has the lowest energy consumption.