ICAR AICE-JRF/SRF (PhD) — Agricultural Engineering subjects 38–43 · India · National Testing Agency for ICAR
Original practice questions written to the published syllabus · not past papersSolar thermal, solar PV, wind and micro-hydro for farms, from sun geometry to sizing a solar pump.
In the exams: GATE AG Section 3 (solar PV in 5 of 8, wind in 5 of 8 papers 2019–26); ICAR AIEEA-PG Unit V; ICAR AICE subject 42 Units 4, 5 and 7; NCEES PE energy sources
ICAR AICE-JRF/SRF (PhD) — Renewable Energy Engineering (subject 42)
Units 4 (solar), 5 (wind) and 7 (power generation and storage) at PG depth: Hottel–Whillier–Bliss analysis, concentration limits, diode model and MPPT algorithms, Weibull wind statistics, capacity factor, battery sizing and storage options, and energy economics.
How our questions for ICAR AICE-JRF/SRF spread across the units of Renewable Energy Sources (Solar, Wind). Difficulty: 1 easy, 45 medium, 22 hard.
| Energy storage | 7 | |
| Solar radiation geometry | 6 | |
| Measurement of solar radiation | 6 | |
| Flat-plate collectors and their efficiency | 6 | |
| Concentrating collectors | 6 | |
| Photovoltaic cell physics and the I-V curve | 6 | |
| Power in the wind and the Betz limit | 6 | |
| Fill factor and MPPT | 5 | |
| Wind turbines and water-pumping windmills | 5 | |
| Solar dryers, cookers, water heaters and stills | 4 | |
| PV system sizing: on-grid and off-grid | 4 | |
| Solar pumps and agri-voltaics | 3 | |
| Energy scenario | 2 | |
| Micro-hydro | 2 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
On a plot of flat-plate collector efficiency against (Ti − Ta)/G, the intercept and slope of the Hottel–Whillier–Bliss line are respectively:
D. FR(τα) and −FRUL
η = FR(τα) − FRUL(Ti − Ta)/G, so the intercept is FR(τα) (optical efficiency) and the slope −FRUL. Writing (τα) and UL without FR would apply only if the whole plate were at inlet temperature with perfect heat removal.
A basin-type solar still has a daily efficiency of 35%. Daily insolation is 20 MJ/m² and the latent heat of vaporisation is 2.35 MJ/kg. What is the daily distillate output per square metre?
C. 2.98 kg/m²
Output = ηH/L = 0.35 × 20 / 2.35 = 2.98 kg/m² per day, in the usual 2–3 L/m² range for basin stills. Omitting efficiency gives 8.51, far above what any still achieves; 0.041 inverts H/L while keeping the efficiency factor (ηL/H = 0.35 × 2.35/20); 10.7 multiplies the correct 2.98 by 3.6, a spurious unit conversion.
What is the density of dry air at 101.325 kPa and 30 °C? (R = 287 J/kg K)
C. 1.165 kg/m³
ρ = p/(RT) = 101325/(287 × 303.15) = 1.165 kg/m³ (≈ 1.165 with T = 303 K). Using 30 in Celsius gives 11.8; 1.225 is the 15 °C sea-level value; using kPa gives a result 1000 times too small. Warm air carries about 5% less power than the standard value at the same speed.
1000 m³ of water is pumped into a reservoir 50 m above the turbine. With a round-trip efficiency of 75%, how much electrical energy can be recovered?
C. 102.2 kWh
Stored energy = ρgVh = 1000 × 9.81 × 1000 × 50 = 490.5 MJ = 136.25 kWh. Recovered = 0.75 × 136.25 = 102.2 kWh. Ignoring efficiency gives 136.2; forgetting the water density (using volume as mass) gives 0.102 kWh. 181.7 kWh divides by the efficiency instead of multiplying.
Why is the solar declination zero at the equinoxes?
C. The sun's rays are then parallel to the equatorial plane, so the noon sun is overhead at the equator
Declination is the angle between the sun–earth line and the equatorial plane; at the equinoxes this line lies in the equatorial plane. The earth's axial tilt does not change, and perihelion occurs in early January, not at an equinox.
The collector heat removal factor FR increases when:
B. The fluid mass flow rate increases, because the fluid temperature rise and hence the mean plate temperature fall
FR = (ṁcp/AcUL)[1 − exp(−AcULF′/ṁcp)] rises towards F′ as ṁ increases, because the plate runs closer to inlet temperature. It falls towards zero as flow goes to zero (stagnation). A higher UL lowers FR.
In agricultural energy auditing, energy used to manufacture fertiliser and machinery is classified as:
C. Indirect energy input
Direct energy is used on the farm itself (diesel, electricity, human and animal labour); energy embodied in manufactured inputs such as fertiliser, pesticides and machinery is indirect. The coefficients used to value them come from a cited table and differ between sources.
Which of these concentrators is a line-focus system that uses rows of nearly flat mirror strips?
C. Linear Fresnel reflector
A linear Fresnel reflector approximates a trough with many flat or slightly curved strips focusing on a fixed linear receiver above them. Dishes and towers are point-focus; a CPC uses two parabolic segments, not flat strips.
The clearness index KT is defined as:
C. The ratio of global horizontal radiation to extraterrestrial horizontal radiation over the same period
KT = H/H0. It is used to correlate the diffuse fraction. n/N is the relative sunshine duration used in Ångström–Prescott, a different quantity.
In the perturb-and-observe MPPT method, if a small increase in operating voltage produces a decrease in array power, the controller should next:
D. Decrease the operating voltage
A power drop after a voltage increase means the operating point has passed the maximum and is on the right side of the peak, so the perturbation direction is reversed. The method then oscillates around the maximum power point.
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