Heat Loss In Winter Research Articles

Energy and emergy based cost–benefit evaluation of building envelopes relative to geographical location and climate

This paper presents an environmental evaluation of building envelopes, made of three different technologies: a traditional air-cavity wall, a plus-insulated wall (with an external cork covering), and a ventilated wall (with external brick panels fixed on extruded frames). An environmental accounting method, namely Emergy Evaluation (EE), was performed for assessing environmental resource use (energy and material flows), both directly and indirectly, for the construction of a façade (1000 m 2). Then, energy use during the building lifetime was assessed as a constant inflow to the building depending on the thermal skills of building envelopes, besides thermal efficiency of air-conditioning system. In particular, this energy inflow is needed for maintaining constant indoor climate conditions (18 °C) and has to balance heat dissipation through envelopes (heat loss in winter and heat gain in summer). Outcomes were compared with an Energy Analysis (EA) based on an embodied energy accounting. Finally, costs for manufacturing walls (with enhanced performance) and benefits (energy saving) were compared in a unique balance, through both EA and EE. Moreover, outcomes were obtained for three scenarios corresponding to three geographic locations (Berlin in northern Europe, Barcelona on the Mediterranean coast and Palermo in the south of Italy). Results highlighted that performances of building envelopes depend on technologies relative to external climate conditions. Different environmental accounting methods, such as EE and EA, provided outcomes with some difference that are not contradictory to each other but complementary.

Seasonal influences on quantitative changes in sweat‐associated anatomy in native and thoroughbred horses

Stereological techniques were used to assess seasonal influences on morphometric characteristics of hair follicles, sweat and sebaceous glands in abattoir pelts of ponies (PN), thoroughbred (TB) and non-thoroughbred (NTB) horses. Volume density of sweat glands increased significantly from winter (0.061) to summer (0.098) in TB, and showed no change in NTB and a positive tendency in PN. There might be a body surface area : volume effect for sweat gland parameters as PN had smaller values than either TB or NTB, probably attributable to control of heat loss in winter. In summer, the skin remained thick and the volume density of sebaceous glands was increased in NTB, in contrast to TB where both were decreased. It is possible that in summer, sebum has a particular importance in NTB to enhance wicking of sweat through the pelt. TB showed significantly higher volume measurements of sebaceous glands than NTB and PN for winter: sebum has probably a special importance for water-proofing in TB in winter. PN showed no significant seasonal changes in sebaceous glands, but had a thinner summer skin. Winter values for hair follicle volume density between equine groups were similar (TB, NTB 0.066; PN 0.059), as was skin thickness (1.14-1.19 mm). The volume density lowered significantly in summer in TB and NTB. The volume of hair follicles under a unit area of skin surface decreased significantly in TB and nonsignificantly in NTB and PN. The seasonal adaptations of the skin shown here were most pronounced in TB and differed between breeds.

The Development of Transparent Water Storage Envelopes (TWSE) through Theoretical Thermal and Optical Analyses

A Transparent Water Storage Envelope (TWSE) is an innovative curtain wall system being developed to improve the overall energy efficiency of commercial buildings by means of minimizing the cooling load in summer and heat loss in winter as well as remaining transparent for facilitating direct utilization of natural light in the daytime. Based on the theoretical thermal analysis, a Convection Baffle Layer (CBL) system was originated. A typical TWSE prototype with CBLs has been investigated, especially from the perspective of incorporating thermal mass benefit into thermal performance in summer. Several optical characteristics of TWSEs are discussed in this paper as a guide for more specific technical designs. This paper mainly reports on the development of TWSEs through theoretical analyses on its thermal performance and optical properties.

Impact on the ocean of extreme Greenland Sea heat loss in the HadCM3 coupled ocean‐atmosphere model

The ocean response to air‐sea flux variability in the Greenland Sea is investigated using a 1000 year run of the coupled ocean‐atmosphere model HadCM3. Evaluation of the density flux reveals that net heat flux anomalies have a greater impact on surface density changes than anomalies in both net evaporation and ice melt/formation. Averaged over the Greenland Sea, the annual mean density flux due to heat loss is 1.8 × 10−6 kg m−2 s−1, an order of magnitude greater than the net evaporation and the ice melt and formation terms, which are −0.1 and −0.2 × 10−6 kg m−2 s−1, respectively. Extreme winter heat loss events reach 250 W m−2 and are associated with reduced ice cover and anomalously strong northerly airflow over the Greenland Sea. They result in enhanced convection and modify the properties of deep water flowing south through the Denmark Strait. The deep water transport increases by about 30% when the strongest and weakest heat loss events are compared, and there is a corresponding reduction in temperature and salinity by up to 2.3°C and 0.38 psu. We also find significant correlations between deep western basin temperatures at 60°, 55°, and 49°N and the Greenland Sea heat flux anomalies which peak at lags of up to 4 years with the time delay increasing toward more southerly latitudes. Our results suggest that Greenland Sea heat flux variability is a key variable for understanding recent observations of significant interannual variability in Denmark Strait transport characteristics.

Mediterranean bottom-current deposits: an example from the Southwestern Adriatic Margin

Abstract The identification of bottom-current deposits is a key to understanding the long-term deep-sea circulation and its changes through geological times. The Southwestern Adriatic Margin (SAM) is a small Mediterranean sub-basin that represents a key site to study bottom-current deposits in a Mediterranean context and hence to improve our knowledge of changes in Mediterranean deep-water circulation during the recent geological past. The SAM is characterized by complex stratification and circulation related to an interaction between two south-flowing bottom water masses: the cold North Adriatic Dense Water (NAdDW), formed in the shallow northern Adriatic through cold wind forcing and winter heat loss, and the highly saline Levantine Intermediate Water (LIW), generated in the Eastern Mediterranean through intense evaporation and flowing along the slope in a depth range of 200–600 m. Chirp-sonar profiles, TOBI mosaics and sediment cores acquired along the SAM reveal distinctive sediment drift types (elongated, plastered and isolated drifts) and extensive fields of sediment waves. Non-depositional and erosional features related to bottom-current activity include moats between drifts and the steep slope, widespread upper-slope erosional areas and extensive furrowed areas, which are particularly developed where change in slope orientation blocks the current circulation. The distribution, morphology and size of bottom-current features along the SAM result from an interaction between current regime and slope morphology, characterized by structural highs perpendicular to the slope contour (e.g. Dauno Seamount), multiple slope incisions (e.g. Bari Canyon and slump scars) and extensive block-slide deposits. Morphobathymetric and seismic stratigraphic data on the SAM show that bottom-current deposits are best developed where the regional slope flattens seaward of a very steep, often erosional, upper slope. The roughness of the lower slope, in particular, seems to correlate with the complexity and decreasing size of the bottom-current deposits. Like other land-locked basins, the Adriatic underwent dramatic palaeogeographical and palaeoceanographic rearrangements during the Late Quaternary sea-level oscillations. Indeed, during the Last Glacial Maximum (LGM), most of the areas where NAdDW is formed today were subaerially exposed. Concurrently, during glacial times the LIW production was probably reduced compared with the present-day conditions. The SAM slope is a key site to study the impact of changing current regime on late Quaternary slope deposits. Other Mediterranean late Quaternary contourite deposits are either in water depths compatible with the LIW, particularly in the case of shallow sill basins (e.g. Sicily, Corsica Channel), or at the slope base reflecting the flow of Mediterranean deep waters. The SAM bottom-current deposits, instead, seems to record the changing interaction between two distinctive bottom-hugging currents along the same pathway.

Thermal design standards for energy efficiency of residential buildings in hot summer/cold winter zones

Factors such as solar heat gain in summer, heat loss in winter, and natural ventilation in transitional seasons must be considered when designing energy-efficient residential buildings for hot summer/cold winter zones. In this paper, the rationale for defining thermal design of energy-efficient buildings is discussed based on results of field tests on pilot buildings and calculations for typical buildings.

Long‐term heat flux variability and winter convection in the Adriatic Sea

Calculations of the Adriatic heat fluxes have been carried out. The most appropriate expressions were used assuming that the Adriatic Sea on average loses heat, as shown by some previous studies. Interannual variations of the heat fluxes were analyzed for the period 1989–1999 using the European Centre for Medium‐Range Weather Forecasts ERA‐40 Reanalysis data set. One of the most relevant issues resulting from the climatological analysis is the presence of an interannual signal and a significant intra‐annual variability during the whole period considered. Large year‐to‐year changes were evidenced, including a net heat gain in some years like in 1994. Interannual yearly heat flux variations largely depend on winter heat losses. Winter convection and dense water formation in the southern Adriatic are directly linked to winter heat loss, although the extent of the vertical mixing is also dependent on the characteristics of the preconditioning period, more specifically of December. Because of mild winter climatic conditions, in some years, winter convection was shown to be completely absent. Separate analyses of the southern and northern Adriatic heat fluxes were carried out as well to see whether the two subbasin fluxes change independently on an interannual timescale. This is especially important considering that the ventilation of the Southern Adriatic Bottom Water takes place through the combined influence of the Northern Adriatic Dense Water and a local vertical convection.

Temporal evolution of thermal structures and winter heat content change from VOS-XBT data in the central Mediterranean Sea

Abstract. Seasonal and year-to-year time evolution of the thermal structure, including the heat content change in the upper water column and its relationship with the surface net heat fluxes, have been studied at five locations in the central Mediterranean Sea. The study is based on temperature profiles collected during XBT surveys (eXpendable Bathy-Thermograph) carried out on ships of opportunity, in the framework of the MFSPP (Mediterranean Forecasting System Pilot Project), between September 1999 and May 2001. The five investigated zones are located in the southern Adriatic, NW Ionian, southern and northern Tyrrhenian, and Ligurian Sea. Gradual erosion of the thermocline in autumn, formation of a mixed layer in winter, and the onset of the stratification in spring, are common properties of the temporal evolution of thermal structures at all five locations. Moreover, in the southern Adriatic, a deep convection took place down to about 600 m in winter 1999/2000. On the other hand, mild climatic conditions and small surface heat loss in autumn and winter 2000/2001 drastically reduced a mixing/convection depth which hardly reached 200 m. Simultaneously, the NW Ionian remained slightly stratified throughout the winter period. The heat storage rate in the upper portion of the water column (down to 450 m) is compared with the air-sea net heat flux at a monthly scale. A heat content decrease is determined by the surface heat loss, and the processes such as lateral advection, or upwelling of the colder waters through the base of the water column (for example, in the southern Adriatic and Ionian Seas). Elsewhere (for example, in the northern Tyrrhenian and Ligurian Seas), the upwelling does not contribute significantly to the heat balance within the water column, since the vertical temperature gradients in deeper layers are negligible. Key words. Oceanography: general (climate and interannual variability; descriptive and regional oceanography) – Oceanography: physical (air-sea interactions)

The snow cover on lakes of the Arctic Coastal Plain of Alaska, U.S.A.

AbstractShallow lakes cover >25% of Alaska’s Arctic Coastal Plain. These remain frozen and snow-covered from October to June. The lake snow is thinner, denser, harder and has less water equivalent than snow on the surrounding tundra. Itcontains less depth hoar than land snow, yet paradoxically is subject to stronger temperature gradients. It also has fewer layers and these have been more strongly affected by wind. Dunes and drifts are better developedon lakes; they have wavelengths of 5–20 m, compared to <5 m on land. Because of these differences, lake snow has roughly half the thermal insulating capacity of land snow. The winter mass balance on lakes is also different because (1) some snow falls into the water before the lakes freeze, (2) some snow accumulates in drifts surrounding the lakes, and (3) prevailing winds lead to increased erosion and thinner snow on the eastern lake sides. Physical models that extrapolate land snow over lakes without appropriate adjustments for depth, density, distribution and thermal properties will under-predict ice thickness and winter heat losses.

Projected Impact of Climate Change on the Energy Budget of the Arctic Ocean by a Global Climate Model

The annual energy budget of the Arctic Ocean is characterized by a net heat loss at the air-sea interface that is balanced by oceanic heat transport into the Arctic. The energy loss at the air-sea interface is due to the combined effects of radiative, sensible, and latent heat fluxes. The inflow of heat by the ocean can be divided into two components: the transport of water masses of different temperatures between the Arctic and the Atlantic and Pacific Oceans and the export of sea ice, primarily through Fram Strait. Two 150-year simulations (1950-2099) of a global climate model are used to examine how this balance might change if atmospheric greenhouse gases (GHGs) increase. One is a control simulation for the present climate with constant 1950 atmospheric composition, and the other is a transient experiment with observed GHGs from 1950 to 1990 and 0.5% annual compounded increases of CO2 after 1990. For the present climate the model agrees well with observations of radiative fluxes at the top of the atmosphere, atmospheric advective energy transport into the Arctic, and surface air temperature. It also simulates the seasonal cycle and summer increase of cloud cover and the seasonal cycle of sea-ice cover. In addition, the changes in high-latitude surface air temperature and sea-ice cover in the GHG experiment are consistent with observed changes during the last 40 and 20 years, respectively. Relative to the control, the last 50-year period of the GHG experiment indicates that even though the net annual incident solar radiation at the surface decreases by 4.6 W(per square meters) (because of greater cloud cover and increased cloud optical depth), the absorbed solar radiation increases by 2.8 W(per square meters) (because of less sea ice). Increased cloud cover and warmer air also cause increased downward thermal radiation at the surface so that the net radiation into the ocean increases by 5.0 Wm-2. The annual increase in radiation into the ocean, however, is compensated by larger increases in sensible and latent heat fluxes out of the ocean. Although the net energy loss from the ocean surface increases by 0.8 W (per square meters), this is less than the interannual variability, and the increase may not indicate a long-term trend. The seasonal cycle of heat fluxes is significantly enhanced. The downward surface heat flux increases in summer (maximum 2 of 19 W per square meters or 23% in June) while the upward heat flux increases in winter (maximum of 16 W per square meters or 28% in November). The increased downward flux in summer is due to a combination of increases in absorbed solar and thermal radiation and smaller losses of sensible and latent heat. The increased heat loss in winter is due to increased sensible and latent heat fluxes, which in turn are due to reduced sea-ice cover. On the other hand, the seasonal cycle of surface air temperature is damped, as there is a large increase in winter temperature but little change in summer.

Ganzjährige Freilandhaltung von Rindern

All-year range beef cattle keeping is a low-cost method, which is widespread in Northeast and Middle Hill regions of Germany. Though there is no winter stabling, animal adaptation to heat loss due to winter weather must be supported by suitable keeping measures. These are littered, wind-protected lying areas and sufficient body energy reserves. Forms of adaptation to heat loss in winter are a reduction in movement activity and more frequenting of the feeding place. Here the turf is completely destroyed, combined with high excrement pollution. To avoid high N-inputs into deeper subsoil, litter must be used at central feeding places. Another solution is decentralised feeding and supplying feed from the stem. Within the framework of preventive consumer protection, monitoring systems are being developed, which regularly assess animal welfare and eco-friendliness.

The Adriatic Sea General Circulation. Part I: Air–Sea Interactions and Water Mass Structure

Abstract A comprehensive historical hydrographic dataset for the overall Adriatic Sea basin is analyzed in order to define the open ocean seasonal climatology of the basin. The authors also define the regional climatological seasons computing the average monthly values of heat fluxes and heat storage from a variety of atmospheric datasets. The long term mean surface heat balance corresponds to a heat loss of 19–22 W m−2. Thus, in steady state, the Adriatic should import about the same amount of heat from the northern Ionian Sea through the Otranto Channel. The freshwater balance of the Adriatic Sea is defined by computing the average monthly values of evaporation, precipitation, and river runoff, obtaining an annual average gain of 1.14 m. The distribution of heat marks the difference between eastern and western Adriatic areas, showing the winter heat losses in different parts of the basin. Climatological water masses are defined for three regions of the Adriatic: (i) the northern Adriatic where seasonal ...

Sensitivity of an atmospheric general circulation model to the parameterization of leads in sea ice

Open-water leads in sea ice dominate the exchange of heat between the ocean and atmosphere in ice-covered regions, and so must be included in climate models. A parameterization of leads used in one such model is compared to observations and the results of a detailed Arctic sea-ice model. Such comparisons, however, are hampered by the errors in observed lead fraction, but the parameterization appears to compare better in winter than in summer. Simulations with an atmospheric general circulation model (AGCM), using prescribed sea-surface temperatures and ice extent, are used to illustrate the effect of parameterized lead fraction on atmospheric climate, and so provide some insight into the importance of improved lead-fraction parameterizations and observations. The effect of leads in the AGCM is largest in Northern Hemisphere winter, with zonal mean surface-air temperatures over ice increasing by up to 5 K when lead fraction is increased from 1% to near 5%. The effect of leads on sensible heat loss in winter is more important than the effect on radiative heat gain in summer. No significant effect on sea-level pressure, and hence on atmospheric circulation, is found, however. Indirect effects, due to feedbacks between the atmosphere and ice thickness and extent, were not included in these simulations, but could amplify the response.

Sensitivity of an atmospheric general circulation model to the parameterization of leads in sea ice

Open-water leads in sea ice dominate the exchange of heat between the ocean and atmosphere in ice-covered regions, and so must be included in climate models. A parameterization of leads used in one such model is compared to observations and the results of a detailed Arctic sea-ice model. Such comparisons, however, are hampered by the errors in observed lead fraction, but the parameterization appears to compare better in winter than in summer. Simulations with an atmospheric general circulation model (AGCM), using prescribed sea-surface temperatures and ice extent, are used to illustrate the effect of parameterized lead fraction on atmospheric climate, and so provide some insight into the importance of improved lead-fraction parameterizations and observations. The effect of leads in the AGCM is largest in Northern Hemisphere winter, with zonal mean surface-air temperatures over ice increasing by up to 5 K when lead fraction is increased from 1% to near 5%. The effect of leads on sensible heat loss in winter is more important than the effect on radiative heat gain in summer. No significant effect on sea-level pressure, and hence on atmospheric circulation, is found, however. Indirect effects, due to feedbacks between the atmosphere and ice thickness and extent, were not included in these simulations, but could amplify the response.

The climatic conditions of polar-type glaciers development in china

Around the Kunlun Peak there are many huge and broad mountains lifting above the Equilibrium Line altitade (ELA). forming the largest glacier distribution centre in China. Here the ELA is very high and the glacier existence is attributed to the unfavorableness of ablation, not the favorablenesses of accumulation. In the ablation period strong evaporation-sublimation and conduction expend a large amount of heat. restraining melting. In addition. meltwater is easy to refreeze, forming superimposed ice and then reducing mass loss. Low air temperature causes low ablation rate and short ablation period. Arid and cold climate is favorable to glacier development. comparable to the polar regions. Nonuniform precipitation decreases heat income during the ablation period and increases heat loss in winter, also resulting in restraining ablation.

Seasonal heat balance in the Gulf of California

Most of the available hydrographic data (1939–1988) from the Gulf of California are used to describe the seasonal cycle of heat storage in the upper 400 m of water. The seasonal cycle of surface heat flux is obtained by using the sea surface temperature from the hydrographic data bank and meteorological data from coastal stations along the gulf. Monthly values of surface heat flux and heat storage are fitted to a mean value plus an annual harmonic. The longitudinal (i.e., along‐gulf) heat flux is then obtained by integrating the difference between the rate of change of heat storage and the surface heat flux. It is found that the surface heat flux has a positive (into the sea) annual mean all along the gulf; the average annual net surface heat flux for the whole gulf being ∼118 W m−2. The southern part of the gulf gains more heat (∼130 W m−2) than the northern part (∼100 W m−2), owing to the larger loss by evaporation in the latter (∼0.6 m/yr versus ∼1 m/yr) caused by lower humidity and stronger winds. These values are in agreement with previous estimates for the northern gulf. The amplitude of the seasonal signal shows a maximum of ∼230 W m−2 in the central part. Winter heat losses occur only from the middle of the gulf, the Guaymas Basin, to its head. There is a strong annual signal superimposed on the average longitudinal heat flux, whose amplitude is larger than the annual harmonic of the surface heat flux. Input of heat from the Pacific Ocean occurs from mid‐March to mid‐July, with a maximum at the mouth in May (21×1012 W). Attempts to explain this flux by diffusive processes were unsuccessful. The proposition that advection is the main longitudinal heat carrier is congruent with the generally accepted circulation patterns.

Thermal Structure of the Lower Great Lakes in a Warm Year: Implications for the Occurrence of Hypolimnion Anoxia

Abstract In this paper, surface heat flux, thermal structure and dissolved oxygen concentrations for the lower Great Lakes are examined for an anomalously warm year, 1983. The year was characterized by large reductions in surface heat losses in winter and above-average surface heat flux gains in summer. On an annual basis, the lakes buffered large surface heat gains in summer months through losses in other months. Observations indicated higher surface water temperatures, significant reductions in duration and extent of ice cover, and an earlier disappearance of the 4°C isotherm, signalling an earlier start to thermal stratification. In response to greater surface heating and low wind conditions, the thermocline formed higher in the water column, and stratification lasted longer than in other years. These conditions contributed to slight hypolimnetic anoxia in the central basin of Lake Erie in the latter half of September.

Daylighting design for the Pacific Museum of flight: Energy impacts

The daylighting performance of the Pacific Museum of Flight in Seathle, WA, has been analyzed using the DOE-2.1C building energy simulation program. The main exhibit areas of this museum are enclosed on three sides by glass walls and the 4500-m 2 roof is completely glazed. Because of the large glass areas, a detailed thermal simulation of the building was carried out during its design phase in order to select glazing parameters that would avoid excessive summer solar heat gain, reduce winter heat loss and, at the same time, provide enough natural light of significantly reduce electric lighting loads. Glazing choices considered included conventional glass, heat mirror, and glass with a low-emissivity coating. On/off, stepped and continuous dimming lighting control systems were analyzed. Daylighting was found to be very effective in reducing annual electric lighting load, peak electrical demand, and the overall annual energy consumption.

Ocean/atmosphere heat fluxes within the Agulhas Retroflection region

The southern section of the Agulhas western boundary current system exhibits unique characteristics as regards ocean/atmosphere heat flux processes. The Agulhas Retroflection region's high heat flux core from 37°S to 41°S, 16°E to 22°E does not demonstrate a distinct annual cycle of turbulent heat fluxes (latent and sensible) as is characteristic of its northern hemisphere counterparts. Rather, a weak semiannual heat flux cycle is found with maximum average losses during winter and summer (200 and 211 W/m2 ) and minimum losses during spring and autumn (185 and 162 W/m2 ). Upstream where the Agulhas Current is closer to land, winter heat losses exceed those of summer, but the differences are small. This behavior contrasts with that encountered at the poleward ends of northern hemisphere western boundary currents where winter heat fluxes are several times those of summer. The main reason for this difference is persistent westerly and southwesterly wind flow over the Agulhas Retroflection region throughout the year which ensures that cold, unsaturated maritime air repeatedly forces loss of heat from the ocean's surface. Spatial heat flux gradients associated with the Agulhas‐Subtropical Convergence surface temperature front are more pronounced in summer than in winter, indicating that cyclogenesis locally may be less seasonally dependent than in the northern hemisphere situation. Average oceanic cooling rates in the core region of the Retroflection, based on net heat flux calculations and a mixed surface layer of 75 m, range from 1.35°C/month during winter to 0.25°C/month during summer. Interannual variability in ocean/atmosphere heat fluxes within the Agulhas Retroflection region often exceeds the variability illustrated by the annual cycle. West of the Agulhas Retroflection core region, interannual sea surface temperature (SST) anomalies are more influential in the generation of heat flux anomalies by virtue of their large temporal variability. This high SST variability is primarily attributed to interannual changes in flux of Agulhas Current water into the southeast Atlantic Ocean. Oceanic heat loss within this warm water zone is an important modifying influence to both ocean and atmosphere, thus meriting further research.

On Windows in Libraries

Windows in libraries are energy expensive and un- necessary. They transfer heat losses in winter and heat gains in sum- mer and create reading difficulties due to sun glare. Windows are unrcliable sources of library lighting because of variations in day- light intensity. They cannot be used safely for ventilation. These factors outweigh the informational and psychological value of view out. Since some library buildings continue to be constructed with large glassed-in areas, a review of the advantages and disadvantages of windows in libraries is pertinent.