BV2 Version | . |
It is structured in a way that makes most commands self explanatory and together
with explanatory help you get guidance on possible ambiguities.
With its customizable input structure, BV2 is unique. In almost every part of the program, you can choose between a
limited amount of input data or more extensive and detailed input. The last option is particularly useful in reconstruction
or in the early stages of construction. The latter option is useful for example in the detail design phase.
You get the calculations results on the screen in front of you. Each time a change is made in any building or technical system,
you can immediately view the results.
The results are available in clear tables, bar charts or duration diagrams.
With the help of BV2 you can easily calculate both design effects and annual energy needs allocated over heating, cooling and electrical systems.
No two buildings are alike! In BV2, you therefore have greater potential to choose between a variety of heat producers, from
a wood burning boiler and a solar heater to a heat pump. It is equally easy to choose between different types of ventilation
systems and controlling them, as it is to choose air- or waterborne comfort cooling or district cooling.
In practical situations you usually have to make several energy calculations on the same building in order to try different
solutions. BV2 is particularly suited to study the consequences of different choices, such as:
What is most profitable, to install air-or waterborne comfort cooling?
What is the difference in cooling and heating if window A is chosen instead of Window B?
What happens to the indoor temperature if I rebuild/build onto my existing building and would like to keep the old cooling system?
Which type of climate control system will provide the lowest electricity consumption?
How does the building’s design and location impact the need for cooling and heating energy?
Which heat production system provide the lowest life-cycle cost, a heat pump or a pellet boiler with solar?
A little about using sustainability graphs for energy and effect calculations
The calculation of the building heat balance in BV2 is based on the yearly outside temperatures. It separates days from nights. Below is a brief review of how the building Heat Balance in the Duration Chart (BV2) can be presented in a graphical form and how it should be interpreted based a sample of what can be viewed on the screen.
Decisive (main) heating power requirements are found on the coldest winter night, while the design cooling power needs are found on the hottest summer day.
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The building’s heating requirements
It is important to understand that the building's heating power requirement (red bar) refers only to the building’s requirement of the added thermal energy for heating in addition to the heat generated by people, lighting, appliances and solar radiation in the building. Its heat energy is sometimes called the heat deficit. The thermal energy need not be equal to the amount of purchased energy, which is influenced by the type of heat that the building has.
If the building has a boiler, the amount of purchased energy is larger due to losses in
combustion in the boiler. If the building is connected to district heating, the amount of
purchased heat is equal to the heat requirements as the heat loss is virtually negligible.
If the building instead has a heat pump, and perhaps also in combination with a solar
heating system, the amount of purchased energy is considerably smaller than the building’
s heating requirements.
In addition to the building’s need of energy for heating, heating energy is needed to heat
the hot water system and the ventilation system. This heat quantity is not represented in
the duration chart above. If the building is ventilated with exhaust air, the ventilation
air is heated directly in the building's rooms. If the ventilation air is supplied via
fan system, the air is heated separately in the air handling unit.
The building’s cooling requirements
During part of the year there is an excess of thermal energy in the building (blue bar), which leads to high indoor temperatures if the excess heat is not removed by means of a comfort cooling system. In everyday speech the surplus heat is called the building cooling requirement. The building cooling requirement is in most cases greater than the purchased energy to the comfort cooling system. How much the difference is between cooling requirement and the purchased energy for the comfort cooling system depends on the type of system the building is equipped with and how the comfort cooling system is designed and dimensioned. For example, the difference between cooling requirements and purchased energy for the building is affected by whether or not the building has air-borne or water-cooling systems, if there is a cooling machine or district heating and if any type of free cooling is used.
To learn more about BV2, please contact us