Entire Heating Period Research Articles

Increasing the efficiency of the condensing boiler

Analysis of existing designs of boilers with low power consumption showed that the low efficiency of the latter is due to the fact that they work in most cases when the heating period in the power range is significantly less than the nominal power. At the same time, condensing boilers do not work in the most optimal mode (in condensing mode) in the central part of Russia, a significant part of their total operating time during the heating season. This is due to existing methods of equipment selection and joint operation with heating systems with quantitative control of the coolant. It was also revealed that for the efficient operation of the heating system, it is necessary to reduce the inertia of the heat generating equipment. Theoretical patterns of thermal processes in the furnace during combustion gas at different radiating surfaces location schemes considering the influence of the very furnace configuration, characterized in that to reduce the work condensing boiler in conventional gas boiler operation is necessary to maintain a higher temperature in the furnace (in the part where spiral heat exchangers are disposed), which is possible when redistributing heat flow - increase the proportion of radiant heat from the secondary burner emitter allow Perey For the operation of the condensing boiler in the design (condensation) mode practically the entire heating period.

Increasing the efficiency of the condensing boiler

Analysis of existing designs of boilers with low power consumption showed that the low efficiency of the latter is due to the fact that they work in most cases when the heating period in the power range is significantly less than the nominal power. At the same time, condensing boilers do not work in the most optimal mode (in condensing mode) in the central part of Russia, a significant part of their total operating time during the heating season. This is due to existing methods of equipment selection and joint operation with heating systems with quantitative control of the coolant. It was also revealed that for the efficient operation of the heating system, it is necessary to reduce the inertia of the heat generating equipment. Theoretical patterns of thermal processes in the furnace during combustion gas at different radiating surfaces location schemes considering the influence of the very furnace configuration, characterized in that to reduce the work condensing boiler in conventional gas boiler operation is necessary to maintain a higher temperature in the furnace (in the part where spiral heat exchangers are disposed), which is possible when redistributing heat flow - increase the proportion of radiant heat from the secondary burner emitter allow Perey For the operation of the condensing boiler in the design (condensation) mode practically the entire heating period.

Energy efficiency evaluation of a shuttle kiln based on field test

With intensified energy restructure in China, energy efficiency of various industrial furnaces and kilns fired by natural gas draws attentions of more and more researchers. In this article, a field test was performed for shuttle kiln popular in ceramics and refractory manufacture industry. The thermal efficiency, main heat loss, and the energy-saving potential were evaluated, and the defects of the existing kilns and improvement measure were clarified. The results show that the overall efficiency was only 13%–15%, if measured in terms of the entire heating period. The energy loss of flue gas accounted up to 50%; the effectiveness of air preheater was as low as only 30%; large amount of cold air infiltration was observed at the venting exit at the bottom of the kiln. The burner controls and gas flow within furnace remain to be optimized.

Custom-designed Laser-based Heating Apparatus for Triggered Release of Cisplatin from Thermosensitive Liposomes with Magnetic Resonance Image Guidance.

Liposomes have been employed as drug delivery systems to target solid tumors through exploitation of the enhanced permeability and retention (EPR) effect resulting in significant reductions in systemic toxicity. Nonetheless, insufficient release of encapsulated drug from liposomes has limited their clinical efficacy. Temperature-sensitive liposomes have been engineered to provide site-specific release of drug in order to overcome the problem of limited tumor drug bioavailability. Our lab has designed and developed a heat-activated thermosensitive liposome formulation of cisplatin (CDDP), known as HTLC, to provide triggered release of CDDP at solid tumors. Heat-activated delivery in vivo was achieved in murine models using a custom-built laser-based heating apparatus that provides a conformal heating pattern at the tumor site as confirmed by MR thermometry (MRT). A fiber optic temperature monitoring device was used to measure the temperature in real-time during the entire heating period with online adjustment of heat delivery by alternating the laser power. Drug delivery was optimized under magnetic resonance (MR) image guidance by co-encapsulation of an MR contrast agent (i.e., gadoteridol) along with CDDP into the thermosensitive liposomes as a means to validate the heating protocol and to assess tumor accumulation. The heating protocol consisted of a preheating period of 5 min prior to administration of HTLC and 20 min heating post-injection. This heating protocol resulted in effective release of the encapsulated agents with the highest MR signal change observed in the heated tumor in comparison to the unheated tumor and muscle. This study demonstrated the successful application of the laser-based heating apparatus for preclinical thermosensitive liposome development and the importance of MR-guided validation of the heating protocol for optimization of drug delivery.

Specification requirements for inter-seasonal heat storage systems in a low energy residential house

This paper aims at providing sizing information concerning a thermal storage system in the case of a low energy consumption building (<50kWh/m2y). Numerical simulations for a reference individual building were run for 23 different cities in Europe. Results show a clear correlation between annual heat demand Qy and annual heating degree-day (HDD): Qy=f1(HDD). There is also a good correlation between power demand and HDD. But as heat coverage of the entire heating period may be too ambitious, the analysis goes further. It presents a correlation between heating demand Q and HDD as a function of the storage system autonomy t of the form Q=1-exp-tτ×Qy with τ=f2(HDD). It also gives the absolute distribution of sorted power demand values as a function of HDD in the form of a power sizing chart. The purpose of this chart is to provide specifications for the sizing of a thermal storage system intended to partially cover energy needs and power demand of a low energy residential house.

Performance evaluation of ground source heat pump system for greenhouse heating in northern China

To investigate the technical, economic, and environmental performance of ground source heat pump system (GSHP) for greenhouse heating, a groundwater-style GSHP was studied in a Chinese solar greenhouse (G1) and a glass-covered multi-span greenhouse (G2) during 2007–2008 heating period in Beijing, China. The heating coefficient of performance (COP) of the GSHPs in G1 and G2 were 3.83 (from Oct. 10, 2007 to Mar.10, 2008) and 3.91 (from Oct.10, 2007 to Feb. 3, 2008), respectively. The daily heating cost per m 2 greenhouse floor were 0.016 US$ m −2 d −1 and 0.058 US$ m −2 d −1 in G1 and G2, respectively. The heating costs of G1 and G2 were lower than gas-fired heating system (GFH) by 8.9% and 11.4%, but were higher than coal-fired heating system (CFH) by 16.5% and 12.9%, respectively. Equivalent carbon dioxide (CO 2 ) emission analysis showed that G1 and G2 reduced CO 2 emission by 41.9% and 44.6%, respectively, compared with CFH, but increased by 46.1% and 43.5% compared with GFH during the entire heating period, assuming that the electricity consumed by G1 and G2 was generated in coal-fired power plant. However, if the electricity energy consumed by GSHP was generated by burning the gas, the GSHP, in fact, emitted 45.9% less CO 2 than GFH in heating the greenhouse. The equivalent CO 2 emission from G2 heating per m 2 area was 3.37 times of that from G1. The test demonstrated that the Chinese solar greenhouse had higher economic and environmental performances than the glass-covered multi-span greenhouse.

On Approximate Solutions for Unsteady Conduction in Slabs with Uniform Heat Flux

In this paper, the Transversal Method of Lines (TMOL) or Rothe's method is employed to obtain analytical expressions of simple form for the unsteady one-dimensional heat conduction in a slab. Initially, the slab is maintained at a uniform temperature, and then a uniform heat flux is applied to its surfaces. Implementation of TMOL generates a sequence of adjoint ordinary differential equations, where the spatial coordinate is the only independent variable and the time becomes a parameter. In spite of the anticipated expectations that the semi-discrete solutions produced by TMOL would yield accurate temperature responses for short times only, detailed calculations demonstrate the opposite trend. Surprisingly, the temperature results associated with two equal time steps are excellent not only for short times, but during the entire heating period.

Switch Arrangement and Power Averaging in Constant Current Calorimetric Heating

In order to minimize the transient effect associated with switching a constant current power supply to different loads, a break-before-make type of switch contact arrangement is shown to be preferable to a make-before-break type of arrangement. Series resistance in the load circuit may be required for low current applications. With a constant heater current, the average heater power for the entire heating period can be precisely determined as the product of the current and the mean value of two particular potential readings. These two readings, symmetrical about the midpoint of the heating period, should be taken at specified intervals as determined by the exponential heat conduction characteristics of the calorimeter assembly.