Blog assignment 1: Research question

Where in the irrigation system of the tree nursery water drops away?

Irrigation optimisation:  where irrigation water could be economised?

Required data:

·         Irrigation amount according to areas

·         Precipitation

·         Terrain division with slopes and  sewers

·         Flow in field-sewers in inflow- and outlet areas

·         Plant type, pot size, pot arrangement

·         Evapotranspiration of the different pot- and planttypes

·         Wind, temperature,  solar radiation

·         Evapotranspiration subsoil

Water loss evaluation

Seepage though/ besides plastic foil

Irrigation water + precipitation water– transpiration – flow sewer inflow-area

leakage pipe system

 flow sewer inflow-area – flow sewer outlet-area

Irrigation optimisation

Soil humidity in pots in the course of a day

Irrigation and precipitation in the course of a day

Flow rate

Optimal irrigation water amount: sufficient humidity in pots with minimal outflow

Needed data set

·         Intra-day  temperature

·         Intra-day  wind velocity

·         Intra-day weight loss div. Pots

·         Intra-day soil humidity in pots

·         Daily precipitation

·         Daily irrigation water amount

·         Intra-day flow sewers inflow and outlet areas

Data Collection

Irrigation amount

Data nursery. Nozzle type and amount, water bills, pump activity. Frequency and time of irrigation.

Calculation irrigation per square meter depeding different areas, plants and pot sizes.

                                                                   

Terrain classification with slopes and  sewers

Data nursery, maps

Precipitation measurement

Precipitation gauges (or raingauges if only liquid precipitation can be measured) are the most common instruments used to measure precipitation. Generally, an open receptacle with vertical sides is used, usually in the form of a right cylinder, with a funnel if its main purpose is to measure rain. Since various sizes and shapes of orifice and gauge heights are used in different countries, the measurements are not strictly comparable (WMO, 1989a). The volume or weight of the catch is measured, the latter in particular for solid precipitation. The gauge orifice may be at one of many specified heights above the ground or at the same level as the surrounding ground. The orifice must be placed above the maximum expected depth of snow cover, and above the height of significant potential insplashing from the ground. For solid precipitation measurement, the orifice is above the ground and an artificial shield should be placed around it. The most commonly used elevation height in more than 100 countries varies between 0.5 and 1.5 m (WMO, 1989a).

The measurement of precipitation is very sensitive to exposure, and in particular to wind.

(World Meteorological Organization, (1989))

Flow rate pipes

To measure the flow rate there are a couple of options. The first would be optical detection. If we can add view ports to your piping and the liquid is not clear it should work. We could use aligned LEDs and photocells for a rough level measurement. Or, even simpler, if there is an access to the pipes, we could measure the water height in the pipe every hour. The next option would be ultrasonic level sensors. I don't know how having multiple on the same line would effect them. If you are just looking for an emergency shut off in case the level drops a single sensor would do.

ExactSonic II - portable ultrasonic flow meter for liquids

This principle of measurement is also referred to as the transit time difference method. For measuring the flow rate of liquids using this technique, ultrasonic pulses are sent and received simultaneously through the medium in the direction of flow and against it. The sensors work alternately as transmitter and receiver. The transit time of the acoustic signals filtered through the medium in the direction of flow is shorter than that against it. The difference in transit time Δt is measured and can be used to calculate the average flow velocity of liquids filtering through the acoustic path. After measuring the flow velocity and with the pipe cross-sectional area, volumetric flow can be calculated.

These ultrasonic flowmeters have many benefits, for example, the measuring instruments produce accurate results in just a matter of minutes, they are easy to install and operate, there is no process interruption and there are no pipe restrictions. As a result, there is no pressure loss and therefore, time and cost savings as the ultrasonic flow meter is easy to install on the pipe.

Advantages of non-invasive measuring with the ultrasonic flowmeters:

• installation without process interruption or shut-down
• easy and cost-effective assembly
• light-weight ergonomic design
• ideal for use in maintenance areas and commissioning
• testing fixed measuring equipment

Device-related advantages of the ultrasonic flow measurement equipment compared to other products:

• no zero point alignment of the flow meter necessary
• coverage of the most frequent industrial applications for flow measurement of liquids with just two transducer sets
• high-capacity data logger with numerous parameters for pipe materials and mediums
• stable and reliable results even under difficult conditions
• excellent reproducibility of results

Measurement-related advantages of the ultrasonic flow meter:

• non-contact measurement
• independent of pressure, temperature, conductivity and viscosity
• unlimited plant availability, as no process interruption
• no pressure losses when measuring flow rate, no risk of leakage, no cleaning necessary
• no mismeasurements as a result of blocked impulse pipes
• logging of lowest flow velocities (min. 0.2 m/s) resulting in high measuring dynamics

(Hönzsch GMBH (2014))

Weight measurement plants

Continous weighing of pots.

Maybe possible to film analogue scale next to watch during day to have continuous data.

Evapotranspiration subsoil

Weight measurement soil

Continous weighing of a part of soil, packed in tissue and stored in the soil when not weighed in order to be able to calculate a realistic transpiration rate.

Tensiometer (Soil humidity)

A tensiometer is a device for monitoring soil water. It consists of a porous cap (usually made of ceramic with very fine pores) connected to a vacuum gauge.The soil humidity must me measured to be able to calculate the water circles of this area. 

Best would be to install several devices on strategic points of the area and to make continuous measures, which can be compared with the irrigation, flowrate and temperature data.

Temperature, Air humidity

Continuous measuring necessary for comparability of data

Analogue measuring

Stationary measuring on fields with thermometer. Continuous notation by hand.

Data logger for humidity, temperature, air pressure and CO2

·         Continuous data recording over long periods owing to the long battery life and the large data memory.

·         The data loggers can operate in an Ethernet network. The measured data is available in real time and it can be displayed and saved simultaneously on a computer.

·         Maximum reliability of measurement data transmission is guaranteed by the integrated Ethernet interface.

·         Easy evaluation and visualisation of measurement data. The powerful SmartGraph3 software is included in the scope of supply.

·         Local visual and acoustic alarms for fast decisions in the field.

·         Modern enclosure with large display.

(E + E Elektronik Ges.m.b.H (2016))

Wind

Wind velocity is less difficult to measure than atmospheric moisture A number of different whirling cup anemometers are available that either register total miles of wind passed in a given time interval or give continuous records of wind velocity These instruments measure only the average values of the horizontal component of the wind To measure the instantaneous velocities in the major direction as well as those to the right and left and up and down is much more difficult and requires specialized equipment Pressure plate anemometers hot wire anemometers or pressure tube anemographs are generally used for this purpose and the scale and frequency of the fluctuations measured depends upon the inertia of the instrument used The wind measurements required in the evaporation equation can be obtained with standard instruments Wind velocity is measured at two levels with a pair of contacting cup type anemometers Wind direction is measured at the upper level only The type of wind record required depends on the kind of humidity instruments being used If continuous records of atmospheric moisture are being obtained as from dew point recorders or hygro thermographs continuous records of wind velocity will be required in order to determine the rate of evaporation for short tune intervals If however only integrated values of atmospheric moisture are being obtained as from chemical absorption hygrometers continuous records of wind velocity are unnecessary but only an indication of the total miles of wind passed during the time interval for which the moisture measurements apply The fact that the required wind value in the evaporation equation is the difference in velocity at the two levels makes it unnecessary to apply a correction factor to the readings of either instrument Wind velocity enters the formula also in the determination of z zi and here actual velocities are required However failure to apply the small correction factors to get true wind speeds at the two levels will result in errors so small they can be neglected.(Charles Warren (1942))

Literature

World Meteorological Organization, (1989): International Workshop on  Precipitation   Measurements B. Sevruk, ed.)

Hönzsch GMBH (2014). Retrieved from http://www.hoentzsch.com/en/products/ultrasonic-ua/ on 18.03.2016.

E + E Elektronik Ges.m.b.H (2016). Retrieved from http://www.epluse.com/en/products/humidity-instruments/humidity-temperature-logging/humlog20/ on 18.03.2016.

Measurement of Evaporation from Land and Water Surfaces (1942) by Charles Warren Thornwaite,Benjamin Holzman