Cold Room Heat Load
Compute the product cooling heat load in a cold room, Q = m·cp·ΔT, from the product mass, its specific heat and the desired temperature change. It is the sensible-heat portion to remove to lower the product temperature — one of the components of the room's total load (which also includes wall transmission, infiltration, lighting, motors and people). It defines the refrigerating capacity needed. Enter the mass, the specific heat and the ΔT.
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Carga térmica de câmara fria
Dimensionar uma câmara fria começa por somar todas as fontes de calor que o sistema de refrigeração precisará remover. Uma das principais é a carga do produto: o calor sensível para baixar a temperatura da mercadoria, Q = m·cp·ΔT, função da massa, do calor específico do produto e da variação de temperatura desejada. Resfriar 1 tonelada de frutas de 25 °C para 5 °C, por exemplo, exige remover uma quantidade considerável de energia — e fazê-lo num tempo razoável define a potência necessária. Mas a carga do produto é só uma das parcelas. A carga térmica total da câmara soma ainda: a transmissão de calor pelas paredes, teto e piso (Q = U·A·ΔT pela envoltória isolada); a infiltração de ar quente pela abertura de portas; o calor liberado por iluminação, motores de ventiladores, pessoas trabalhando; o calor latente de congelamento (se o produto muda de fase) e até o calor de respiração de frutas e hortaliças vivas. Para produtos congelados, abaixo do ponto de congelamento, o calor latente do gelo domina. Subdimensionar a carga resulta numa câmara que nunca atinge a temperatura; superdimensionar desperdiça capital e energia. Esta calculadora cobre a parcela de calor sensível do produto. Informe a massa, o calor específico e o ΔT.
Related Tools
Food Specific Heat (Choi-Okos)
Compute a food's specific heat by the Choi-Okos equations, cp = 4.18·Xwater + 1.55·Xprotein + 1.71·Xfat + 1.42·Xcarbohydrate + 0.91·Xash (kJ/kg·K), from the component mass fractions. Since water has a very high specific heat, wetter foods heat and cool more slowly. It is essential in computing the heat loads of cooking, refrigeration and freezing. Enter the water, protein, fat, carbohydrate and ash fractions.
Pile Bearing Capacity
Calculate a pile's ultimate bearing capacity, Q_ult = Q_p + Q_l, summing the point (tip) resistance Q_p (kN) and the side (skin friction) resistance Q_l (kN). The pile is the DEEP foundation element used when surface soil lacks capacity for the structure's loads — it transfers loads to deeper, stronger subsoil layers. This transfer occurs by TWO mechanisms acting at once: TIP resistance (the pile bears on a firm layer at its base, like a column, mobilizing the soil resistance under the tip) and SIDE resistance (friction and adhesion between the pile's lateral surface and surrounding soil, along its whole length). Their proportion defines the behavior: END-bearing piles (crossing soft soil to bear on rock or firm soil) work mainly by the tip; FLOATING or friction piles (driven in homogeneous soil, no firm layer) work mainly by side friction. The ultimate capacity, divided by a safety factor (typically 2), gives the design allowable load. Determining Q_p and Q_l — by theoretical formulas, SPT-based semi-empirical methods (Aoki-Velloso, Décourt-Quaresma) or load tests — is the central deep-foundation design calculation. Enter the tip resistance and the side resistance.
Brake Power Dissipated
Calculate the power dissipated by a brake under torque, P = T·(2π·n/60), from the braking torque T (N·m) and the rotation n (rpm). Dissipated power is the rate at which the brake converts mechanical energy to heat — the product of braking torque and angular velocity. It differs from total braking ENERGY: energy is the total heat generated (joules), while power is the INTENSITY of that heat generation (watts), and it determines the brake's steady-state temperature. A brake dissipating much energy but slowly (low power) heats little; one dissipating the same energy fast (high power) heats much more. Dissipated power is critical in brakes working CONTINUOUSLY or repetitively: retention brakes on long descents, industrial equipment brakes (hoists, cranes, conveyors holding load), and dynamometers (which measure engine power precisely by dissipating it in a brake). There, the steady-state dissipated power sets the COOLING capacity needed (ventilation, water cooling) to keep temperature stable. Equating dissipated power to cooling capacity gives the equilibrium temperature. Enter the braking torque and the rotation.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.