Sewage Source Heat Pump System Research Articles

Research on the PCA-based Intelligent Fault Detection Methodology for Sewage Source Heat Pump System

As an energy-saving and environmentally friendly technology, sewage source heat pump is rapidly developing to be widely implemented in urban distributed energy system. However, in the lifecycle, the faulty operation of sewage source heat pump system (SSHPs) results in energy wastage, low efficiency, system unreliability and shorter equipment life. A novel PCA-based fault detection methodology is proposed for fault detection of SSHPs. Analyzing of the square prediction error (SPE) and Hotelling’s T2 principal component analysis (PCA) is a valid intelligent detection method to figure out faulty operation. Approximately 4,800 records of running state parameters was investigated from a 500,000 m2 sewage source heat pump central heating system of community building in Xi’an, China. The PCA-based fault detection model of the SSHPs was established, and the SPE and Hotelling’s T2 was calculated and analyzed. The analysis results presented that the PCA-based fault detection methodology can distinguish anomalies from normal operation, and availably detect the faults of SSHPs. Hence, the PCA-based fault detection methodology can ensure the healthy and efficient operation of SSHPs, and improve the application prospect of the system.

Experimental Study of the Performance of a New Developed Heat Pump Water Heater with Frozen Evaporator

Heat pumps are a part of the environmentally friendly technologies using renewable energy and have been utilized in HVAC systems. A heat pump water heater unit with frozen type evaporator was designed and developed. And a test bed was constructed to determine the performance of the unit. In the experiment, a parallel helical coil type evaporator was used in the unit to extract latent heat from the sewage. The data (dynamic COP and other parameters) was obtained in three processes(including the first freezing, melting, and the second freezing) at different water temperatures (8.2℃ and 13.8℃). Results show that compare with traditional water source heat pumps, the newly designed unit with the frozen evaporator can reduce the required water amounts as a heat source by more than 90%. The higher initial temperature of hot water and sewage, the higher temperature of sewage after melting. Meanwhile, with the increase of the initial temperature of hot water and sewage, the comprehensive COP was greater. This paper will provide a reference for the sewage source heat pump system to extract the latent heat from the sewage.

Research of pump energy consumption model in the sewage-source heat pump system and optimization method

Operation energy consumption of heat pump systems is one of the key problems for system design. This study establishes the models of transportation energy consumption ratio and transportation distance limit and puts forward the concepts of new economic specific frictional resistance. According to existing calculation formulas of specific frictional resistance, calculation formulas for more economic specific frictional resistance are deduced by combining with economic indexes. In this way, a range (30–400 Pa/m) of new economic specific frictional resistance is obtained to determine the transportation energy consumption ratio of water. On this basis, the pipe network is designed to reduce and control the transportation energy consumption ratio of pumps to 15%-20%.

The Performance Simulation Analysis of the Sewage-source Heat Pump Heater Unit Dealing with Large Temperature Difference

Generally, the temperature of domestic waste water is high above 30℃. However, when dealt with by common sewage-source heat pump system, temperature difference between inlet side and outlet side is small as 5℃. It leads to manifold cycles and energy waste. To acquire a unit of heat pump water heater of sewage dealing with large temperature difference with high energy utilization rate, through which the cold water (about 5℃) can be heated once to hot water (about 45℃) to reach the temperature for daily use and waste water (about 30℃) can be rapidly dropped to cold water (about 6℃) to satisfy the standard of waste water emissions. In this paper, two staged series of heat pump water heater dealing with large temperature difference is proposed. And performance factor of system is analyzed through simulation by MATLAB so as to find the optimum middle operating point. This method ensures pattern operating in large temperature difference but in small flow at both the hot and cold sides. At the same time, it avoids the lasting elevation of condensing temperature and the constant reduction of temperature in evaporation, which helps to facilitate the stability and optimal performance of the operating unit.

Optimization Study on the Heat Transfer Area of the Sewage Source Heat Pump System Based on Year-round Coefficient of Performance

Based on simulation model of the sewage source heat pump system (SSHPS), weigh the influence of coefficient of performance under different work conditions, the ACOP was defined and as the optimization function, with the heat exchange areas of the evaporator, condenser and the sewage-midwater heat exchanger as the optimization variables. The optimization mathematical models for the on-off control scheme were set up to calculate the ACOP to study the optimal design and areas matching between the evaporator, condenser and sewage-midwater heat exchanger. Comparison with the initial design parameters and different optimization designs with HSPF, SEER and EER, the ACOP optimization is nearer to the objective energy conservation effect.

Key Problem Analysis and Solution on Intake Water and Heat Transfer of Sewage-Source Heat Pump System

Changing "high consumption energy, low temperature heat to the indoor, waste heat to the environment", and turning the HVAC harmoniously into the natural ecological cycle, conform to the trend of the development of ecological architecture. Heat pump technology is a way of HVAC energy saving the most practical. Although low heat and cold source of the city sewage is ideal, but the quality is very unstable, can not meet the operation requirements of heat exchange equipment. This paper analyzes the key problems of the sewage side in sewage source heat pump technology application in the present: hair dirt clog sewage heat exchanger; fouling in heat surface reduces the heat transfer performance, and results in large heat-transfer equipment in the practical application. According to the key problems of sewage side, this paper prevents hair clogged with large tube heat exchanger; reduces the fouling thermal resistance, and enhances heat transfer process using the heat exchanging technology of circulating fluidized bed.

Frequency Control Characteristics of a Direct-Mode Untreated Sewage Source Heat Pump in the Heating Mode

An untreated sewage source heat pump system directly makes use of the urban raw sewage instead of that treated by a sewage plant. At present In China, most systems adopt the indirect mode for avoiding the harmful effect of the sewage on the heat pump unit. In this article a direct-mode untreated sewage source heat pump system, which shows less theoretical analysis of the mathematical model, is theoretically designed and analyzed to simulate the system dynamic characteristics in the heating mode. The results show that the system COP changes from 4.1 to 3.4 and the heating capacity from 9.5 to 15.3 kW when the sewage inlet temperature is 12°C and the frequency increases from 18 to 32 HZ. The condenser heat-transfer coefficient increases with the frequency reducing while the change trend of evaporator heat-transfer coefficient is the opposite. The highest values of them are 303 and 1617 W.m−2•K−1, respectively. The frequency control simulation supplies the operation adjustment with theoretical instructions and some reference values.

Characteristics Study of Sewage Source Heat Pump System Based on Heat Transfer Enhancement and Acoustic Cavitation Decontamination

Put forward an application of ultrasonic cavitation technology of the sewage source heat pump system to solve the problem of controlling pollution and emphatically discusses the principle of acoustic cavitation and the effect, to conduct a feasibility analysis of Anti-fouling in sewage source heat pump sewage side. Through analysis principle of ultrasonic cavitation and heat transfer enhancement for carrying the experiment, study the pattern of scaling in heat exchange tube for different velocity and viscosity, effect in flow rate on the ultrasonic cleaning wastewater, Effect in ultrasonic treatment time on the descaling result. Obtain that it can enhancement transfer for 48%.

The Research on the Design and its Dynamic Characteristics of Shell and Tube Sewage Heat Exchanger

According to the design parameter of practical engineering, shell and tube sewage heat exchanger is chosen as heat exchanger of secondary sewage-source heat pump system. This paper commences from the design calculation of shell and tube sewage heat exchanger, followed by the analysis of dynamic characteristics influencing rule based on the chosen size. The influence of inlet temperature and outlet temperature on tube temperature and the influence of signal curve of different inlet temperature on outlet temperature are all included.

The Contrast Experimental Study of Sewage Source Heat Pump System and Ground Source Heat Pump System in Hot Summer and Cold Winter Area

For two practical engineering case in a University in Guilin, this paper mainly introduces the performance of sewage-source heat pump and ground source heat pump and compare the running status in two kinds of system. The studies have shown that the sewage source heat pump unit COP at about 3.9, the system COP at about 3.3, ground source heat pump unit COP at about 4.5, the system COP at about 3.4.

The Dynamic Characteristics and Design of a Plate Sewage Heat Exchanger

According to the design parameters of the actual project. In this essay, the plate heat exchanger will be selected as the heat exchanger of secondary sewage-source heat pump system . The plate heat exchanger was designed first calculation, according to the selected plate heat exchanger structure size, flow rate of the change on the influence of the dynamic characteristics, such as inlet velocity and outlet velocity on wall temperature, the influence of different inlet velocity variation signal effects of curves for exit temperature, etc.

Study on Characteristics of Ultrasonic Descaling and Heat Transfer Enhancement in Sewage Source Heat Pump System

sewage heat exchanger is important to collect heat energy in sewage source heat pump system. Heat transfer enhancement effect is not obvious while the chemical methods and manual cleaning is applying to remove the heat exchangers fouling in the long-term operation. Here sets an ultrasonic incrustation removal physical model in heat exchanger structure to antiscaling and descaling simultaneously. The acoustic cavitation technology can be used in sewage source heat pump systems for the experimental results and decontamination rate reaches 50%.

Flow characteristics of the raw sewage for the design of sewage-source heat pump systems.

The flow characteristics of raw sewage directly affect the technical and economic performance of sewage-source heat pump systems. The purpose of this research is to characterize the flow characteristics of sewage by experimental means. A sophisticated and flexible experimental apparatus was designed and constructed. Then the flow characteristics of the raw sewage were studied through laboratorial testing and theoretical analyses. Results indicated that raw sewage could be characterized as a power-law fluid with the rheological exponent n being 0.891 and the rheological coefficient k being 0.00175. In addition, the frictional loss factor formula in laminar flow for raw sewage was deduced by theoretical analysis of the power-law fluid. Furthermore, an explicit empirical formula for the frictional loss factor in turbulent flow was obtained through curve fitting of the experimental data. Finally, the equivalent viscosity of the raw sewage is defined in order to calculate the Reynolds number in turbulent flow regions; it was found that sewage had two to three times the viscosity of water at the same temperature. These results contributed to appropriate parameters of fluid properties when designing and operating sewage-source heat pump systems.

Application of a heat pump system using untreated urban sewage as a heat source

Untreated urban sewage contains large amounts of thermal energy; and its temperature is suitable as a heat source in heat pumps for the heating and cooling of buildings. However, it is not widely used in heat pump systems due to the problem of filth. This paper presents an untreated sewage source heat pump (USSHP) system in which auto-avoiding-clogging equipment is used to continuously capture suspended solids in the sewage. Thus, the block problems caused by filtration and fouling in the heat exchanger tubes can be efficiently resolved in this system. In an actual engineering application, the characteristic parameters of USSHP system are tested under typical operating conditions for heating status. Based on the test results, the performances of the USSHP system are examined. The results indicate that the thermal resistance of the convective heat transfer and fouling on the sewage side in the sewage exchanger is 80% of its total thermal resistance. The COP of the heat pump unit and the COP of the USSHP system are 4.3 and 3.6, respectively.

Analysis of Biological Dirt on the Sewage-Source Heat Pump Exchange Surface

This experiment research the dirt adhere on heat exchanger in the sewage-source heat pump system，which contained moisture content test, ash content test, a digital microscope observation, scanning electron microscope observation, X-ray diffractometer analysis. The experimental results show that the heat exchange surface dirt moisture content is between 90.10% ~ 95.80%. The microflora of dirt is mainly staphylococcus and bacillus, and preferentially attach on rough position. Dirt main inorganic crystal component is SiO2 and Mg (SiO3).

Experimental Study on New Sewage Source Heat Pump Unit

By the analysis of the current technical conditions and existing problems, some improvements are carried out on the urban sewage source heat pump unit. are as follows: Refrigerants side switch sewage source heat pump system, dual-purpose heat exchange for evaporating and condensing & wastewater can enter the unit directly are of the main features of the improved units. Some important techniques, such as inverter screw compressor and variable compressor inner volume ratio are used to the improved unit at the same time. From the authoritative organization’s test, the improved sewage-source heat pump unit has an excellence performance in the nominal cooling and heating conditions.

Lanzhou City Sewage Heat Utilization Measurement Analysis

According to the actual operation of the pick sewage-source heat pump system established by the equivalent of heating, refrigerating capacity sewage equation of lanzhou city sewage contain energy are calculated.

Design and Research on One Avoiding-Clogging Equipment in Untreated Sewage Heat Pump Air Conditioning System

Appling urban untreated sewage as a cool and heat source of the heat pump air conditioning system is considered to be an effective way to develop urban sewage resource and a critical technique to serve the building energy system.Applications of technical difficulties are to solve the jam on sewage dirt to tube of heat exchanger and pipes. The multi-filter surface backwash technology is used to separate the suspended solids from the sewage and clean the dirt on the grille. By describing the filtration technique in the sewage source heat pump system to introduce the principle of operation and control process of the multi-filter surface backwash technology. By using in commercialese, the technology is proved to be feasible and reliability. These methods could serve as a reference for designing and application untreated sewage source heat pump systems.

Performance and Benefits Evaluation of Two Water-Source Heat Pump Systems for District Heating

The heating source of a district heating (DH) system in Beijing was reformed from coal boilers to a groundwater heat pump (GWHP) system and a sewage source heat pump (SSHP) system. This study aims to evaluate the actual performance and benefits of two water-source heat pump systems. We found total energy savings and primary energy saving rate due to the retrofit to be 950 tons of standard coal equivalent (TCE) every year and 34.6%, respectively. Field test results indicated the necessity of system performance improvement. Appropriate approaches to improve the system performance were discussed.

A Certain City Public Building Energy Consumption and Energy Saving of Economic Research and Statistics

In this paper, the main public buildings, Lang fang City, Hebei province, the research summary and statistical power to the city building a sewage treatment plant sewage source heat pump system operating on-site monitoring, the monitoring results of economic analysis with traditional heating methods from the initial investment and operation of both comprehensive economic analysis and comparison.