# Calculating Heating Time of Lube Oil SAE 40 - 19000 Liters at 20° C to 40° C

• amit4644
This assumes that the heater is running at full power and there are no heat losses. In summary, to find the time needed to heat up the lube oil in a closed loop circuit with a heater of 85 kW, you can use the equation Time = (Volume of Oil x Specific Heat Capacity x Delta T) / (Power of Heater x Efficiency). For the given scenario, the time needed is approximately 456.2 hours.
amit4644

## Homework Statement

I have problem in calculating heating time of Lube Oil ( SAE 40 ). There is a tank of Lube Oil ( SAE 40) of 19000 liters at 20° C. this oil has to be heated up from 20° C to 40° C with help of a heater of 85 kW through which oil flows at 4800 liter/hour and back to tank.

How much time it will take to heat up complete tank from 20° C to 40° C. it is a closed loop circuit and small distance. just oil from tank flows at 4800 liter/hour through 85kW heater and then goes back to tank.

any suggestions for finding time needed ??

Thanks

## The Attempt at a Solution

To calculate the time needed to heat up the lube oil, you need to use the equation: Time = (Volume of Oil x Specific Heat Capacity x Delta T) / (Power of Heater x Efficiency) where: Volume of Oil = 19000 liters Specific Heat Capacity = 1.84 kJ/kgK Delta T = 20° C Power of Heater = 85 kW Efficiency = 0.8 Therefore, the time needed to heat up the lube oil is: Time = (19000 x 1.84 x 20) / (85 x 0.8) = 456.2 hours

To calculate the heating time of Lube Oil SAE 40, we need to use the formula Q = mcΔT, where Q is the heat energy required, m is the mass of the oil, c is the specific heat capacity of the oil, and ΔT is the change in temperature. In this case, we can assume that the specific heat capacity of Lube Oil SAE 40 is approximately 2.1 J/g°C.

First, we need to calculate the mass of the oil in the tank. Given that the tank has a volume of 19000 liters, we can convert this to mass using the density of Lube Oil SAE 40, which is approximately 0.88 g/mL. This gives us a mass of 19000 liters x 0.88 g/mL = 16720 kg.

Next, we need to calculate the heat energy required to raise the temperature of the oil from 20°C to 40°C. This can be done by substituting the values into the formula: Q = (16720 kg) x (2.1 J/g°C) x (40°C - 20°C) = 7027200 J.

Since we know that the heater has a power of 85 kW and the oil flows at a rate of 4800 liters/hour, we can calculate the heating time using the formula t = Q/P, where t is the time, Q is the heat energy, and P is the power. Substituting the values, we get t = (7027200 J) / (85,000 W) = 82.6 seconds.

Therefore, it will take approximately 82.6 seconds to heat up the complete tank of Lube Oil SAE 40 from 20°C to 40°C. However, this calculation assumes ideal conditions and does not take into account any heat loss or other factors that may affect the heating time. It is always important to consider these factors and make adjustments accordingly in real-world situations.

## 1. How do you calculate the heating time of lube oil?

The heating time of lube oil can be calculated by using the formula: Heating Time = (Volume x Specific Heat Capacity x Temperature Difference) / Heat Transfer Coefficient. In this case, the volume is 19000 liters, the specific heat capacity is that of SAE 40 lube oil, and the temperature difference is 20° C. The heat transfer coefficient can be determined based on the type of heating method being used.

## 2. What is the specific heat capacity of SAE 40 lube oil?

The specific heat capacity of SAE 40 lube oil is approximately 1.9 J/g°C. This value may vary slightly depending on the specific brand and composition of the lube oil.

## 3. How does the temperature difference affect the heating time of lube oil?

The temperature difference directly affects the heating time of lube oil. The larger the temperature difference, the faster the oil will heat up. In this case, a 20° C difference between the initial temperature (20° C) and the desired temperature (40° C) will result in a shorter heating time.

## 4. Can different heating methods affect the heating time of lube oil?

Yes, different heating methods can affect the heating time of lube oil. For example, using a direct heat source, such as a heater, will heat the oil faster compared to indirect heat methods, such as using a heat exchanger.

## 5. What are the factors that can affect the accuracy of the calculated heating time for lube oil?

The accuracy of the calculated heating time for lube oil can be affected by various factors, such as the accuracy of the specific heat capacity value used, the efficiency of the heating method, and any external factors that may impact the heating process (e.g. wind, ambient temperature). It is important to consider all of these factors when calculating the heating time to ensure accuracy.

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