Calculation of enthalpy value in containers

1 Does the following response meet the requirements? 1.1. The unit of enthalpy is joules per kilogram, and the unit of mass is kilograms; the product of these two gives units of joules. 1.2. Joule is a unit of energy, and subtracting joules from each other still yields joules, which remains within the category of energy. 2 The issue described in point 1 seems a bit confusing – what exactly is required?

There is now a heat storage tank containing saturated steam and saturated water, which is then made available for use by customers who require steam. What needs to be determined now is how much steam is stored in the heat storage tank. One step in the formula involves multiplying the specific enthalpy of the steam in the tank by the mass of water and steam present there. What can this formula be used to calculate?

1. I didn’t understand the description; let’s first clarify whether it means the following: 1.1. The saturated water vapor inside the heat accumulator is in a saturated state. 1.2. The saturated vapor is supplied for use by users. 1.3. It is necessary to determine the amount of saturated vapor present. 2. If that’s indeed what it means, then let’s proceed: 2.1. The enthalpy value of the steam, multiplied by the mass of the steam, gives the thermal energy of the steam. 2.2. What is the meaning of multiplying the enthalpy value of the steam by the mass of the saturated water? 2.3. Since the mass of the steam is known from 2.1., which means the amount of steam is also known and the result is already available, what more is needed? 3. In a two-phase mixed medium in a saturated state, as the steam humidity changes from 0 to 1, the enthalpy value changes significantly; it seems difficult to obtain results based solely on the information mentioned above. 4. What is the purpose of solving this problem? For example, if it is to charge users for steam, then using a steam flow meter would be a more direct approach. 5. The parameters of a saturated liquid or saturated vapor single phase can be obtained directly, and the calculations are also straightforward. Obtaining the parameters of the mixed phase is more complicated

1 If only static values or transient values are required, the interface between the gas phase and the liquid phase can be determined using a level gauge; thereafter, the volumes of the gas phase and the liquid phase can be calculated separately based on the shape of the container. 2 The volume of the liquid phase, once determined, can be used to calculate the mass of saturated water by employing the density of saturated water. 3 For the volume of the gas phase, a steam dryness value can be assumed to estimate the density of saturated steam, from which the mass of saturated steam can be calculated. But what is the use of these transient values?

Well, there is saturated steam and saturated water in the heat storage tank, and the supply of steam to the end-users is controlled through valves. My previous idea was that if the pressure of the steam supplied to the end-users is 1 MPA and the flow rate is 20 t/h, with steam continuously being released from the heat storage tank to meet the users’ needs, then given that both the pressure and flow rate remain constant, I wondered how many kilograms of steam are stored in the heat storage tank

1. Once the requirements are clear, things become easier to handle. 2. But can the information mentioned above solve the problem? Let’s give it a try: 2.1. Since the saturated vapor pressure is known, it’s necessary to assume a value for the steam dryness fraction; for example, 0.95, which corresponds to nearly dry steam. This allows us to determine the density of the steam. By relating density to mass flow rate, we can obtain the volume flow rate, which in turn can be linked to the volume of the heat accumulator. 2.2. In the heat accumulator, there is both saturated vapor and saturated water, but the ratio between the two is unknown. A steam ratio ranging from a certain value to 100% can meet the 20 t/h requirement; the only difference lies in the flow velocity within the steam volume. Therefore, it is necessary to know the ratio between the two, which can be determined using a level gauge and the shape of the equipment; otherwise, a ratio of 2.3 must be assumed. Since the volume of the heat storage tank is unknown, it is still not possible to determine the amount of steam available. The volume is needed in order to proceed. Knowing the amount of steam available does not mean that steam at a rate of 20 t/h can be supplied continuously – only can it be estimated for how long such steam supply will be possible. 4. Whether the regenerator is a steam-generation device or an intermediate storage device, steam output can be met only if steam is continuously supplied from the outside or generated continuously

My personal understanding is that it should be the total energy that this container can output

Well, this is the only way to explain it; I’m not sure how foreigners approach the calculation