Energy Savings Analysis for Operation of Steam Cushion System for Sensible Thermal Energy Storages

The paper presents an analytical discussion of how to improve the energy efficiency of the steam cushion system operation for a Thermal Energy Storage (TES) tank. The EU’s green deal 2050 target policy requires an increase in the energy efficiency of energy production and use, as well as an increase in the share of renewable energy in the overall energy production balance. The use of energy-efficient TES is considered as one of the most important technologies to achieve the objectives of this EU policy. The analyses presented in the paper of energy-efficient operation of steam cushion (SC) systems were carried out by using operational data received from three District Heating Systems (DHSs) that supply heat and electricity to one of the largest cities in Poland and are equipped with the TES systems. These three analyzed TESs differ in capacities from 12,800 to 30,400 m3, tank diameters from 21 to 30 m and shell height from 37 to 48.2 m. The main purpose of using a steam cushion system in the TES tank is to protect the water stored in it against the absorption of oxygen from the surrounding atmospheric air through the surge chamber and safety valves located on the roof of the tank. The technical solutions presented here for the upper orifice for charging and discharging hot water into/from the tank and the suction pipe for circulating water allow to us achieve significant energy savings in the steam cushion systems. Both the upper orifice and the end of suction pipe are movable through the use of pontoons. Thanks to the use of this technical solution, a stable insulating water layer is created above the upper orifice in the upper part of the TES tank, where convective and turbulent transport of heat from the steam cushion space to the hot water stored in the tank is significantly limited. Ultimately, this reduces the heat flux by approximately 90% when compared to the classic technical solutions of steam cushion systems in TES tanks, i.e., for the upper orifice and circulation water pipe. The simplified analysis presented in the paper and comparison of its results with experimental data for heat flow from the steam cushion space to hot water stored in the upper part of the TES tank fully confirms the usefulness of the heat-flow models used.

To calculate the axial dimensions of inkjet devices for hydraulic transport of sand and gravel materials

The article presents the results of the dredger in a deep deposit of sand and gravel materials. It was found that when the diameter of the suction pipe exceeds the diameter of the inlet mixing chamber by 150 mm, the actual pressure from the ejector does not exceed one meter, and with an increase in the supply of the suction pump as a result of a sharp jump in hydraulic resistance, the vacuum is disrupted. It was also found that the effect on the calculated compression ratio of the jet apparatus increases with an increase in the injection coefficient and the input velocity of the injected stream.

Development and test of a combined radon sub-slab suction and sub-slab drainage system

To ensure a healthy indoor environment, the indoor air level of the radioactive gas radon must be kept low according to the WHO. This can be achieved by installing a radon sub-slab suction system. In buildings with a basement at the same time a sub-slab drainage system is often necessary. This paper describes results from a project, aiming to combine a radon sub-slab suction system with a sub-slab drainage system. A combined system will minimize the number of pipes when constructing new buildings and will also provide an easier retrofitting method for adding a radon sub-slab suction system to buildings with an existing sub-slab drainage system. In the project, it was found that the combination of the two functionalities required an airtight system to lower the pressure under the ground slab, an unhampered drainage of ground water and a prevention of odour from the drains. To meet these requirements, a prototype of a well with a water trap, a water outlet and a separate suction pipe for the air outlet was developed. A low voltage fan was installed in the suction pipe. The system was installed in a detached house with a 104 m2 basement. After installation, the pressure reduction over the ground slab in the basement was measured to be able to investigate the effect of the suction system independently of the radon exposure. The results showed a reduction of the pressure in the farthest corners under the ground slab by approximately 0.6 to 1.9 Pa compared to the pressure over the ground slab. We concluded that a combined radon sub-slab suction and sub-slab drainage system is possible with the designed well, although the use of a stronger fan will be necessary to meet the identified test objective of pressure reduction ΔP ≥ 1-3 Pa.

Impeller in suction pipe Thai Phaya-Nakh for agriculture

Purpose The suction pipes are important in agriculture and are used widely in water management and agricultural–mechanical industry in ASEAN. Thus, this paper aims to present design of new impeller in suction pipe and include shape blade impeller to optimize for suction head, which has been higher than efficiency local-type by the performance. It mostly depends on the hydrodynamic characteristics, e.g. lift, drag and ratio, which is known as the “Thai Phaya-Nakh pipe”. Design/methodology/approach By approach NACA methodology and use applied technique: leading edge of blade, skew-line, cambered-line, developed area and advanced number etc., for analyzing data which the result of CFD simulation. Findings The models were tested in field by using motor at rotation speed 1500 rpm and found that the summarized average suction efficiency of the new impeller was estimated to be 72%, which has been greater than that of the local-type impeller with an average suction efficiency of 28% to 2.6 times. In addition, the amount of required electrical energy was reduced by 18%. Originality/value Then after analyzing the data from the static pressure distribution flow rate of impeller models, it is found that the new curved impeller has higher flow rate than the local type impeller. Thus, this study suggests the shape new impeller has higher flow rate than the local type impeller.

Reconstruction of the suction pipeline with a change in the bell of electrified the pumping stations of the Volga irrigation system

The article deals with the actual problems of the Volga irrigation system that arise during operation, related to large water losses in the irrigation channel, cavitation and permanent blockages of the suction pipe. The analysis of the system operation revealed significant shortcomings of the pumping station that prevent efficient operation. Solutions for optimization of pumping stations that supply water to irrigation fields are structurally developed and presented. The main advantages of reconstruction of the suction pipe with a pipeline based on the original version are described.

Fluctuation of Inducer Recirculation Stemming From Diffuser Stall in Centrifugal Turbomachinery Near Surge Condition

This work investigates the unsteady fluctuation of inducer recirculation stemming from the diffuser stall that occurs near the surge condition. Experiments and unsteady numerical simulation were utilized for the investigation. Inducer recirculation is known to occur near the surge occurrence flow rate, where the flow rate has a positive slope of the performance curve and the recirculation extends to the upstream of the impeller inlet when decreasing the flow rate more. However, few papers have investigated the unsteady phenomenon of the recirculation, even though the surge is what causes it. Clarifying the recirculation phenomenon is essential in terms of expanding the operation range to the lower flow rate for centrifugal turbomachinery. This was our motivation for investigating the unsteady oscillation phenomenon of the inducer recirculation. We investigated a single-stage centrifugal blower with the maximum pressure rise ratio of 1.2 and focused on the flow rates near surge occurrence. The blower was equipped with an open type centrifugal impeller, a vane-less diffuser, and a scroll casing. The blower performance and pressure time-history data were obtained by experiments. Unsteady simulations using large eddy simulation (LES) were conducted to investigate the flow field in the blower for each flow rate. The obtained performance curve showed that the positive slope of the pressure rise at the lower flow rate was due to the impeller stall and that the inducer recirculation extending upstream of the suction pipe near the slope of the curve was flat. LES analysis revealed that this inducer recirculation had two typical fluctuation peaks, one at 20% of the rotation frequency and the other at 95%. We also found that the stall cell at the impeller inlet propagated in the circumferential direction and swirled at almost the same frequency as the impeller rotation. In addition, the fluctuation at the diffuser derived from the diffuser rotating stall propagated to the suction pipe.