The numerical simulation of utilizer of soil heat and heat receiver in joint operation

The numerical model of the joint work of borehole heat exchanger and evaporator of the heat pump is developed. The design of the evaporator is shelltube heat exchanger with segmental baffles with a boiling in the U-shaped tubes. The design of ground heat exchanger is heat exchanger with two U-shaped tubes, which are arranged in a vertical borehole. The effect on the system temperature of soil, the multiplicity of circulation in the evaporator heat exchanger, the filler of borehole is modeled by the developed model

Influence of ground heat source parameters and consumer on characteristics of geothermal heat pump system

Features of heat supply system based on the use of ground are investigated with the help of the method of numerical simulation. The variables are the parameters characterizing the heat source and the consumer: the average temperature ofthe soil, the area and the radiative properties of the surface heating panels, air temperature of heated space. It was found that the maximum energy efficiency of the system is achieved by using a low-temperature floor heating system

Method of calculation and analysis of joint operation of circuit loop of ground heat exchangers and heat pump

The method of heat calculation of the joint work of borehole heat exchangers and heat pump circuits in quasi-stationary regime is developed. The effect of the heat pump efficiency of heat exchangers design values, refrigerant superheating in evaporator, temperatures of heat source and heat consumer were analyzed on the base of the developed method

Hexa-μ-chlorido-hexa­chlorido(η6-hexa­methyl­benzene)trialuminium(III)lanthanum(III) benzene solvate

In the title compound, [Al3LaCl12(C12H18)]·C6H6, all mol­ecules are located on a mirror plane. Three chloridoaluminate groups and a hexa­methyl­benzene mol­ecule are bound to the central lanthanum(III) ion, forming a distorted penta­gonal bipyramid with the η6-coordinated arene located at the apical position. The hexa­methyl­benzene ligand disordered between two orientations in a 1:1 ratio is also involved in parallel-slipped π–π stacking inter­molecular inter­actions with a benzene solvent mol­ecule [centroid–centroid distance 3.612 (4) Å]

Remote atomic clock synchronization via satellites and optical fibers

In the global network of institutions engaged with the realization of International Atomic Time (TAI), atomic clocks and time scales are compared by means of the Global Positioning System (GPS) and by employing telecommunication satellites for two-way satellite time and frequency transfer (TWSTFT). The frequencies of the state-of-the-art primary caesium fountain clocks can be compared at the level of 10e-15 (relative, 1 day averaging) and time scales can be synchronized with an uncertainty of one nanosecond. Future improvements of worldwide clock comparisons will require also an improvement of the local signal distribution systems. For example, the future ACES (atomic clock ensemble in space) mission shall demonstrate remote time scale comparisons at the uncertainty level of 100 ps. To ensure that the ACES ground instrument will be synchronized to the local time scale at PTB without a significant uncertainty contribution, we have developed a means for calibrated clock comparisons through optical fibers. An uncertainty below 50 ps over a distance of 2 km has been demonstrated on the campus of PTB. This technology is thus in general a promising candidate for synchronization of enhanced time transfer equipment with the local realizations of UTC . Based on these experiments we estimate the uncertainty level for calibrated time transfer through optical fibers over longer distances. These findings are compared with the current status and developments of satellite based time transfer systems, with a focus on the calibration techniques for operational systems